81915386 has 16 divisors (see below), whose sum is σ = 141360000. Its totient is φ = 34873200.

The previous prime is 81915371. The next prime is 81915389. The reversal of 81915386 is 68351918.

It is not an unprimeable number, because it can be changed into a prime (81915389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17261 + ... + 21488.

It is an arithmetic number, because the mean of its divisors is an integer number (8835000).

Almost surely, 2^81915386 is an apocalyptic number.

81915386 is a deficient number, since it is larger than the sum of its proper divisors (59444614).

81915386 is a wasteful number, since it uses less digits than its factorization.

81915386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38909.

The product of its digits is 51840, while the sum is 41.

The square root of 81915386 is about 9050.7119057011. The cubic root of 81915386 is about 434.2986646461.

The spelling of 81915386 in words is "eighty-one million, nine hundred fifteen thousand, three hundred eighty-six".