81057956 has 36 divisors (see below), whose sum is σ = 165717468. Its totient is φ = 34590528.

The previous prime is 81057941. The next prime is 81057961. The reversal of 81057956 is 65975018.

It can be written as a sum of positive squares in 2 ways, for example, as 43112356 + 37945600 = 6566^2 + 6160^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53546 + ... + 55038.

It is an arithmetic number, because the mean of its divisors is an integer number (4603263).

Almost surely, 2^81057956 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 81057956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82858734).

81057956 is an abundant number, since it is smaller than the sum of its proper divisors (84659512).

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

81057956 is a wasteful number, since it uses less digits than its factorization.

81057956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1788 (or 1779 counting only the distinct ones).

The product of its (nonzero) digits is 75600, while the sum is 41.

The square root of 81057956 is about 9003.2192020410. The cubic root of 81057956 is about 432.7780403371.

It can be divided in two parts, 8105 and 7956, that added together give a palindrome (16061).

The spelling of 81057956 in words is "eighty-one million, fifty-seven thousand, nine hundred fifty-six".