81386672 has 20 divisors (see below), whose sum is σ = 157828440. Its totient is φ = 40656768.

The previous prime is 81386663. The next prime is 81386677. The reversal of 81386672 is 27668318.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81386677) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29279 + ... + 31937.

It is an arithmetic number, because the mean of its divisors is an integer number (7891422).

Almost surely, 2^81386672 is an apocalyptic number.

It is an amenable number.

81386672 is a deficient number, since it is larger than the sum of its proper divisors (76441768).

81386672 is a wasteful number, since it uses less digits than its factorization.

81386672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4580 (or 4574 counting only the distinct ones).

The product of its digits is 96768, while the sum is 41.

The square root of 81386672 is about 9021.4562017448. The cubic root of 81386672 is about 433.3622692052.

The spelling of 81386672 in words is "eighty-one million, three hundred eighty-six thousand, six hundred seventy-two".