81908356362497 has 32 divisors (see below), whose sum is σ = 96710278717440. Its totient is φ = 67922960132160.

The previous prime is 81908356362491. The next prime is 81908356362523. The reversal of 81908356362497 is 79426365380918.

It is not a de Polignac number, because 81908356362497 - 2²⁰ = 81908355313921 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (71).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81908356362497.

It is not an unprimeable number, because it can be changed into a prime (81908356362491) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13825448 + ... + 18840374.

It is an arithmetic number, because the mean of its divisors is an integer number (3022196209920).

It is a 1-persistent number, because it is pandigital, but 2⋅81908356362497 = 163816712724994 is not.

Almost surely, 2^{81908356362497} is an apocalyptic number.

It is an amenable number.

81908356362497 is a deficient number, since it is larger than the sum of its proper divisors (14801922354943).

81908356362497 is a wasteful number, since it uses less digits than its factorization.

81908356362497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5015621.

The product of its (nonzero) digits is 470292480, while the sum is 71.

The spelling of 81908356362497 in words is "eighty-one trillion, nine hundred eight billion, three hundred fifty-six million, three hundred sixty-two thousand, four hundred ninety-seven".