81938910 has 32 divisors (see below), whose sum is σ = 201452832. Its totient is φ = 21317120.

The previous prime is 81938893. The next prime is 81938917. The reversal of 81938910 is 1983918.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81938917) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32079 + ... + 34538.

It is an arithmetic number, because the mean of its divisors is an integer number (6295401).

Almost surely, 2^81938910 is an apocalyptic number.

81938910 is an abundant number, since it is smaller than the sum of its proper divisors (119513922).

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

81938910 is a wasteful number, since it uses less digits than its factorization.

81938910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66668.

The product of its (nonzero) digits is 15552, while the sum is 39.

The square root of 81938910 is about 9052.0113786937. The cubic root of 81938910 is about 434.3402338167.

The spelling of 81938910 in words is "eighty-one million, nine hundred thirty-eight thousand, nine hundred ten".