81959660 has 48 divisors (see below), whose sum is σ = 178977792. Its totient is φ = 31492800.

The previous prime is 81959659. The next prime is 81959723. The reversal of 81959660 is 6695918.

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, 100655 + ... + 101465.

It is an arithmetic number, because the mean of its divisors is an integer number (3728704).

Almost surely, 2^81959660 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 81959660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89488896).

81959660 is an abundant number, since it is smaller than the sum of its proper divisors (97018132).

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

81959660 is a wasteful number, since it uses less digits than its factorization.

81959660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1014 (or 1012 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 81959660 is about 9053.1574602456. The cubic root of 81959660 is about 434.3768944589.

The spelling of 81959660 in words is "eighty-one million, nine hundred fifty-nine thousand, six hundred sixty".