81615457 has 8 divisors (see below), whose sum is σ = 101754432. Its totient is φ = 63596400.

The previous prime is 81615439. The next prime is 81615491. The reversal of 81615457 is 75451618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81615457 - 2¹⁵ = 81582689 is a prime.

It is a super-2 number, since 2×81615457² = 13322165642637698, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81615857) 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, 529894 + ... + 530047.

It is an arithmetic number, because the mean of its divisors is an integer number (12719304).

Almost surely, 2^81615457 is an apocalyptic number.

It is an amenable number.

81615457 is a deficient number, since it is larger than the sum of its proper divisors (20138975).

81615457 is a wasteful number, since it uses less digits than its factorization.

81615457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1059959.

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

The square root of 81615457 is about 9034.1273513273. The cubic root of 81615457 is about 433.7679622822.

The spelling of 81615457 in words is "eighty-one million, six hundred fifteen thousand, four hundred fifty-seven".