81915069 has 16 divisors (see below), whose sum is σ = 111421440. Its totient is φ = 53515440.

The previous prime is 81915049. The next prime is 81915079. The reversal of 81915069 is 96051918.

It is not a de Polignac number, because 81915069 - 2⁵ = 81915037 is a prime.

It is a super-2 number, since 2×81915069² = 13420157058549522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81915049) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82164 + ... + 83154.

It is an arithmetic number, because the mean of its divisors is an integer number (6963840).

Almost surely, 2^81915069 is an apocalyptic number.

It is an amenable number.

81915069 is a deficient number, since it is larger than the sum of its proper divisors (29506371).

81915069 is a wasteful number, since it uses less digits than its factorization.

81915069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1520.

The product of its (nonzero) digits is 19440, while the sum is 39.

The square root of 81915069 is about 9050.6943932496. The cubic root of 81915069 is about 434.2981044222.

The spelling of 81915069 in words is "eighty-one million, nine hundred fifteen thousand, sixty-nine".