81513957 has 16 divisors (see below), whose sum is σ = 124692480. Its totient is φ = 46399152.

The previous prime is 81513941. The next prime is 81513961. The reversal of 81513957 is 75931518.

It is not a de Polignac number, because 81513957 - 2⁴ = 81513941 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81513907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1857 + ... + 12902.

It is an arithmetic number, because the mean of its divisors is an integer number (7793280).

Almost surely, 2^81513957 is an apocalyptic number.

It is an amenable number.

81513957 is a deficient number, since it is larger than the sum of its proper divisors (43178523).

81513957 is a wasteful number, since it uses less digits than its factorization.

81513957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15032.

The product of its digits is 37800, while the sum is 39.

The square root of 81513957 is about 9028.5080162782. The cubic root of 81513957 is about 433.5880710630.

The spelling of 81513957 in words is "eighty-one million, five hundred thirteen thousand, nine hundred fifty-seven".