81932505 has 16 divisors (see below), whose sum is σ = 132445824. Its totient is φ = 43246080.

The previous prime is 81932489. The next prime is 81932519. The reversal of 81932505 is 50523918.

It is not a de Polignac number, because 81932505 - 2⁴ = 81932489 is a prime.

It is a Curzon 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, 26701 + ... + 29610.

It is an arithmetic number, because the mean of its divisors is an integer number (8277864).

Almost surely, 2^81932505 is an apocalyptic number.

It is an amenable number.

81932505 is a deficient number, since it is larger than the sum of its proper divisors (50513319).

81932505 is a wasteful number, since it uses less digits than its factorization.

81932505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56416.

The product of its (nonzero) digits is 10800, while the sum is 33.

The square root of 81932505 is about 9051.6575830066. The cubic root of 81932505 is about 434.3289163539.

The spelling of 81932505 in words is "eighty-one million, nine hundred thirty-two thousand, five hundred five".