81915845 has 16 divisors (see below), whose sum is σ = 107602560. Its totient is φ = 59371200.

The previous prime is 81915833. The next prime is 81915871. The reversal of 81915845 is 54851918.

It is not a de Polignac number, because 81915845 - 2¹⁸ = 81653701 is a prime.

It is a congruent 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, 14711 + ... + 19499.

It is an arithmetic number, because the mean of its divisors is an integer number (6725160).

Almost surely, 2^81915845 is an apocalyptic number.

It is an amenable number.

81915845 is a deficient number, since it is larger than the sum of its proper divisors (25686715).

81915845 is a wasteful number, since it uses less digits than its factorization.

81915845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5116.

The product of its digits is 57600, while the sum is 41.

The square root of 81915845 is about 9050.7372627869. The cubic root of 81915845 is about 434.2994758193.

The spelling of 81915845 in words is "eighty-one million, nine hundred fifteen thousand, eight hundred forty-five".