81619481372 has 24 divisors (see below), whose sum is σ = 167805088752. Its totient is φ = 34245936000.

The previous prime is 81619481353. The next prime is 81619481381. The reversal of 81619481372 is 27318491618.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81619481372.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71345129 + ... + 71346272.

It is an arithmetic number, because the mean of its divisors is an integer number (6991878698).

Almost surely, 2^81619481372 is an apocalyptic number.

It is an amenable number.

81619481372 is an abundant number, since it is smaller than the sum of its proper divisors (86185607380).

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

81619481372 is a wasteful number, since it uses less digits than its factorization.

81619481372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142691429 (or 142691427 counting only the distinct ones).

The product of its digits is 580608, while the sum is 50.

The spelling of 81619481372 in words is "eighty-one billion, six hundred nineteen million, four hundred eighty-one thousand, three hundred seventy-two".