81157465 has 16 divisors (see below), whose sum is σ = 100583568. Its totient is φ = 62816256.

The previous prime is 81157451. The next prime is 81157471. The reversal of 81157465 is 56475118.

It can be written as a sum of positive squares in 8 ways, for example, as 4787344 + 76370121 = 2188^2 + 8739^2 .

It is a cyclic number.

It is not a de Polignac number, because 81157465 - 2²⁵ = 47603033 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34569 + ... + 36841.

It is an arithmetic number, because the mean of its divisors is an integer number (6286473).

Almost surely, 2^81157465 is an apocalyptic number.

It is an amenable number.

81157465 is a deficient number, since it is larger than the sum of its proper divisors (19426103).

81157465 is a wasteful number, since it uses less digits than its factorization.

81157465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2508.

The product of its digits is 33600, while the sum is 37.

The square root of 81157465 is about 9008.7438081011. The cubic root of 81157465 is about 432.9550647010.

The spelling of 81157465 in words is "eighty-one million, one hundred fifty-seven thousand, four hundred sixty-five".