81057792 has 96 divisors (see below), whose sum is σ = 220147200. Its totient is φ = 26517504.

The previous prime is 81057761. The next prime is 81057797. The reversal of 81057792 is 29775018.

It is a tau number, because it is divible by the number of its divisors (96).

It is a self number, because there is not a number n which added to its sum of digits gives 81057792.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81057797) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 485293 + ... + 485459.

It is an arithmetic number, because the mean of its divisors is an integer number (2293200).

Almost surely, 2^81057792 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81057792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110073600).

81057792 is an abundant number, since it is smaller than the sum of its proper divisors (139089408).

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

81057792 is a wasteful number, since it uses less digits than its factorization.

81057792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 39.

The square root of 81057792 is about 9003.2100941831. The cubic root of 81057792 is about 432.7777484651. Note that the first 4 decimals are identical.

The spelling of 81057792 in words is "eighty-one million, fifty-seven thousand, seven hundred ninety-two".