81865372 has 24 divisors (see below), whose sum is σ = 150052896. Its totient is φ = 39006528.

The previous prime is 81865369. The next prime is 81865373. The reversal of 81865372 is 27356818.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81865373) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25438 + ... + 28474.

It is an arithmetic number, because the mean of its divisors is an integer number (6252204).

Almost surely, 2^81865372 is an apocalyptic number.

It is an amenable number.

81865372 is a deficient number, since it is larger than the sum of its proper divisors (68187524).

81865372 is a wasteful number, since it uses less digits than its factorization.

81865372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3357 (or 3355 counting only the distinct ones).

The product of its digits is 80640, while the sum is 40.

The square root of 81865372 is about 9047.9484967588. The cubic root of 81865372 is about 434.2102586432.

The spelling of 81865372 in words is "eighty-one million, eight hundred sixty-five thousand, three hundred seventy-two".