81858944 has 32 divisors (see below), whose sum is σ = 172675800. Its totient is φ = 38520832.

The previous prime is 81858943. The next prime is 81858947. The reversal of 81858944 is 44985818.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81858943) 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, 16634 + ... + 20985.

Almost surely, 2^81858944 is an apocalyptic number.

It is an amenable number.

81858944 is an abundant number, since it is smaller than the sum of its proper divisors (90816856).

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

81858944 is a wasteful number, since it uses less digits than its factorization.

81858944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37650 (or 37638 counting only the distinct ones).

The product of its digits is 368640, while the sum is 47.

The square root of 81858944 is about 9047.5932711412. The cubic root of 81858944 is about 434.1988937379.

The spelling of 81858944 in words is "eighty-one million, eight hundred fifty-eight thousand, nine hundred forty-four".