81915412791390 has 64 divisors (see below), whose sum is σ = 203373388707840. Its totient is φ = 21094194741120.

The previous prime is 81915412791307. The next prime is 81915412791419. The reversal of 81915412791390 is 9319721451918.

It is a congruent number.

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, 93870925 + ... + 94739544.

It is an arithmetic number, because the mean of its divisors is an integer number (3177709198560).

Almost surely, 2^{81915412791390} is an apocalyptic number.

81915412791390 is an abundant number, since it is smaller than the sum of its proper divisors (121457975916450).

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

81915412791390 is a wasteful number, since it uses less digits than its factorization.

81915412791390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188610977.

The product of its (nonzero) digits is 4898880, while the sum is 60.

The spelling of 81915412791390 in words is "eighty-one trillion, nine hundred fifteen billion, four hundred twelve million, seven hundred ninety-one thousand, three hundred ninety".