81457515 has 16 divisors (see below), whose sum is σ = 144813600. Its totient is φ = 43443936.

The previous prime is 81457469. The next prime is 81457543. The reversal of 81457515 is 51575418.

81457515 is a `hidden beast` number, since 81 + 4 + 575 + 1 + 5 = 666.

It is not a de Polignac number, because 81457515 - 2⁹ = 81457003 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81457515.

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, 301560 + ... + 301829.

It is an arithmetic number, because the mean of its divisors is an integer number (9050850).

Almost surely, 2^81457515 is an apocalyptic number.

81457515 is a deficient number, since it is larger than the sum of its proper divisors (63356085).

81457515 is a wasteful number, since it uses less digits than its factorization.

81457515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603403 (or 603397 counting only the distinct ones).

The product of its digits is 28000, while the sum is 36.

The square root of 81457515 is about 9025.3817093794. The cubic root of 81457515 is about 433.4879727509.

The spelling of 81457515 in words is "eighty-one million, four hundred fifty-seven thousand, five hundred fifteen".