81964725220 has 96 divisors (see below), whose sum is σ = 200348176896. Its totient is φ = 27585100800.

The previous prime is 81964725151. The next prime is 81964725239. The reversal of 81964725220 is 2252746918.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4286080 + ... + 4305160.

It is an arithmetic number, because the mean of its divisors is an integer number (2086960176).

Almost surely, 2^81964725220 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 81964725220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100174088448).

81964725220 is an abundant number, since it is smaller than the sum of its proper divisors (118383451676).

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

81964725220 is a wasteful number, since it uses less digits than its factorization.

81964725220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19661 (or 19659 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 46.

The spelling of 81964725220 in words is "eighty-one billion, nine hundred sixty-four million, seven hundred twenty-five thousand, two hundred twenty".