81976980 has 72 divisors (see below), whose sum is σ = 233749152. Its totient is φ = 21464576.

The previous prime is 81976919. The next prime is 81976981. The reversal of 81976980 is 8967918.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81976981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 725404 + ... + 725516.

It is an arithmetic number, because the mean of its divisors is an integer number (3246516).

Almost surely, 2^81976980 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81976980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116874576).

81976980 is an abundant number, since it is smaller than the sum of its proper divisors (151772172).

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

81976980 is a wasteful number, since it uses less digits than its factorization.

81976980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 48.

The square root of 81976980 is about 9054.1139820526. The cubic root of 81976980 is about 434.4074903151.

The spelling of 81976980 in words is "eighty-one million, nine hundred seventy-six thousand, nine hundred eighty".