81928938 has 32 divisors (see below), whose sum is σ = 201672576. Its totient is φ = 21607488.

The previous prime is 81928927. The next prime is 81928949. The reversal of 81928938 is 83982918.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81928927) and next prime (81928949).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74481 + ... + 75572.

It is an arithmetic number, because the mean of its divisors is an integer number (6302268).

Almost surely, 2^81928938 is an apocalyptic number.

81928938 is an abundant number, since it is smaller than the sum of its proper divisors (119743638).

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

81928938 is a wasteful number, since it uses less digits than its factorization.

81928938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150078.

The product of its digits is 248832, while the sum is 48.

The square root of 81928938 is about 9051.4605451275. The cubic root of 81928938 is about 434.3226133052.

The spelling of 81928938 in words is "eighty-one million, nine hundred twenty-eight thousand, nine hundred thirty-eight".