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21432240 = 24325172103
BaseRepresentation
bin101000111000…
…0011110110000
31111022212111200
41101300132300
520441312430
62043211200
7350112444
oct121603660
944285450
1021432240
11111093a5
127216b00
1345952cb
142bbc824
151d35460
hex14707b0

21432240 has 180 divisors, whose sum is σ = 77201904. Its totient is φ = 5326848.

The previous prime is 21432239. The next prime is 21432241. The reversal of 21432240 is 4223412.

It is an interprime number because it is at equal distance from previous prime (21432239) and next prime (21432241).

It is a tau number, because it is divible by the number of its divisors (180).

It is a super-2 number, since 2×214322402 = 918681822835200, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (21432241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 208029 + ... + 208131.

Almost surely, 221432240 is an apocalyptic number.

21432240 is a gapful number since it is divisible by the number (20) 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 21432240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38600952).

21432240 is an abundant number, since it is smaller than the sum of its proper divisors (55769664).

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

21432240 is a wasteful number, since it uses less digits than its factorization.

21432240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 21432240 is about 4629.4967329074. The cubic root of 21432240 is about 277.7724618835.

Adding to 21432240 its reverse (4223412), we get a palindrome (25655652).

The spelling of 21432240 in words is "twenty-one million, four hundred thirty-two thousand, two hundred forty".