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121680 = 24325132
BaseRepresentation
bin11101101101010000
320011220200
4131231100
512343210
62335200
71014516
oct355520
9204820
10121680
1183469
125a500
1343500
14324b6
15260c0
hex1db50

121680 has 90 divisors (see below), whose sum is σ = 442494. Its totient is φ = 29952.

The previous prime is 121661. The next prime is 121687. The reversal of 121680 is 86121.

It can be divided in two parts, 1216 and 80, that added together give a 4-th power (1296 = 64).

121680 is an esthetic number in base 5, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 3 ways, for example, as 576 + 121104 = 24^2 + 348^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121687) by changing a digit.

121680 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 9354 + ... + 9366.

2121680 is an apocalyptic number.

121680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221247).

121680 is an abundant number, since it is smaller than the sum of its proper divisors (320814).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121680 is a wasteful number, since it uses less digits than its factorization.

121680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45 (or 23 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 121680 is about 348.8266044900. The cubic root of 121680 is about 49.5533553853.

The spelling of 121680 in words is "one hundred twenty-one thousand, six hundred eighty".

Divisors: 1 2 3 4 5 6 8 9 10 12 13 15 16 18 20 24 26 30 36 39 40 45 48 52 60 65 72 78 80 90 104 117 120 130 144 156 169 180 195 208 234 240 260 312 338 360 390 468 507 520 585 624 676 720 780 845 936 1014 1040 1170 1352 1521 1560 1690 1872 2028 2340 2535 2704 3042 3120 3380 4056 4680 5070 6084 6760 7605 8112 9360 10140 12168 13520 15210 20280 24336 30420 40560 60840 121680