81929164 has 6 divisors (see below), whose sum is σ = 143376044. Its totient is φ = 40964580.

The previous prime is 81929153. The next prime is 81929201. The reversal of 81929164 is 46192918.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10241142 + ... + 10241149.

Almost surely, 2^81929164 is an apocalyptic number.

It is an amenable number.

81929164 is a deficient number, since it is larger than the sum of its proper divisors (61446880).

81929164 is a wasteful number, since it uses less digits than its factorization.

81929164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20482295 (or 20482293 counting only the distinct ones).

The product of its digits is 31104, while the sum is 40.

The square root of 81929164 is about 9051.4730292920. The cubic root of 81929164 is about 434.3230126627.

The spelling of 81929164 in words is "eighty-one million, nine hundred twenty-nine thousand, one hundred sixty-four".