81865944 has 32 divisors (see below), whose sum is σ = 227406000. Its totient is φ = 27288576.

The previous prime is 81865939. The next prime is 81865951. The reversal of 81865944 is 44956818.

It is a super-2 number, since 2×81865944² = 13404065574022272, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81865944.

It is a congruent 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, 189289 + ... + 189720.

Almost surely, 2^81865944 is an apocalyptic number.

It is an amenable number.

81865944 is an abundant number, since it is smaller than the sum of its proper divisors (145540056).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81865944 is a wasteful number, since it uses less digits than its factorization.

81865944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379024 (or 379014 counting only the distinct ones).

The product of its digits is 276480, while the sum is 45.

The square root of 81865944 is about 9047.9801060789. The cubic root of 81865944 is about 434.2112699283.

The spelling of 81865944 in words is "eighty-one million, eight hundred sixty-five thousand, nine hundred forty-four".