81301725403566 has 32 divisors (see below), whose sum is σ = 169689551505408. Its totient is φ = 25919785927200.

The previous prime is 81301725403511. The next prime is 81301725403601. The reversal of 81301725403566 is 66530452710318.

It is a congruent number.

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, 27012510 + ... + 29871041.

It is an arithmetic number, because the mean of its divisors is an integer number (5302798484544).

Almost surely, 2^{81301725403566} is an apocalyptic number.

81301725403566 is an abundant number, since it is smaller than the sum of its proper divisors (88387826101842).

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

81301725403566 is a wasteful number, since it uses less digits than its factorization.

81301725403566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56893936.

The product of its (nonzero) digits is 3628800, while the sum is 51.

The spelling of 81301725403566 in words is "eighty-one trillion, three hundred one billion, seven hundred twenty-five million, four hundred three thousand, five hundred sixty-six".