81929786 has 16 divisors (see below), whose sum is σ = 130649760. Its totient is φ = 38422800.

The previous prime is 81929777. The next prime is 81929821. The reversal of 81929786 is 68792918.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6836 + ... + 14511.

It is an arithmetic number, because the mean of its divisors is an integer number (8165610).

Almost surely, 2^81929786 is an apocalyptic number.

81929786 is a deficient number, since it is larger than the sum of its proper divisors (48719974).

81929786 is a wasteful number, since it uses less digits than its factorization.

81929786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21469.

The product of its digits is 435456, while the sum is 50.

The square root of 81929786 is about 9051.5073882752. The cubic root of 81929786 is about 434.3241117757.

The spelling of 81929786 in words is "eighty-one million, nine hundred twenty-nine thousand, seven hundred eighty-six".