81195980 has 48 divisors (see below), whose sum is σ = 179020800. Its totient is φ = 30875328.

The previous prime is 81195973. The next prime is 81196013. The reversal of 81195980 is 8959118.

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, 91097 + ... + 91983.

It is an arithmetic number, because the mean of its divisors is an integer number (3729600).

Almost surely, 2^81195980 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 81195980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89510400).

81195980 is an abundant number, since it is smaller than the sum of its proper divisors (97824820).

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

81195980 is a wasteful number, since it uses less digits than its factorization.

81195980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1118 (or 1116 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 41.

The square root of 81195980 is about 9010.8811999715. The cubic root of 81195980 is about 433.0235432123.

The spelling of 81195980 in words is "eighty-one million, one hundred ninety-five thousand, nine hundred eighty".