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81016320 = 2935711137
BaseRepresentation
bin1001101010000…
…11011000000000
312122110001111110
410311003120000
5131220010240
612012243320
72002425120
oct465033000
9178401443
1081016320
1141805840
1223170540
1313a27b68
14aa8cc80
1571a4c80
hex4d43600

81016320 has 320 divisors, whose sum is σ = 325264896. Its totient is φ = 16711680.

The previous prime is 81016319. The next prime is 81016337. The reversal of 81016320 is 2361018.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Saint-Exupery number, since it is equal to the product of the sides of a Pythagorean triangle: 548 × 420 × 352.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 591292 + ... + 591428.

Almost surely, 281016320 is an apocalyptic number.

81016320 is a gapful number since it is divisible by the number (80) 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 81016320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162632448).

81016320 is an abundant number, since it is smaller than the sum of its proper divisors (244248576).

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

81016320 is a wasteful number, since it uses less digits than its factorization.

81016320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181 (or 165 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 81016320 is about 9000.9066210021. The cubic root of 81016320 is about 432.7039277989.

Adding to 81016320 its reverse (2361018), we get a palindrome (83377338).

The spelling of 81016320 in words is "eighty-one million, sixteen thousand, three hundred twenty".