81337072563 has 32 divisors (see below), whose sum is σ = 122280960000. Its totient is φ = 53425884096.

The previous prime is 81337072513. The next prime is 81337072633. The reversal of 81337072563 is 36527073318.

81337072563 is a `hidden beast` number, since 8 + 13 + 3 + 7 + 0 + 72 + 563 = 666.

It is not a de Polignac number, because 81337072563 - 2²⁶ = 81269963699 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81337072513) 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, 981903 + ... + 1061511.

It is an arithmetic number, because the mean of its divisors is an integer number (3821280000).

Almost surely, 2^81337072563 is an apocalyptic number.

81337072563 is a deficient number, since it is larger than the sum of its proper divisors (40943887437).

81337072563 is a wasteful number, since it uses less digits than its factorization.

81337072563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80176 (or 80170 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 45.

The spelling of 81337072563 in words is "eighty-one billion, three hundred thirty-seven million, seventy-two thousand, five hundred sixty-three".