81863957775599 has 4 divisors (see below), whose sum is σ = 83251482483720. Its totient is φ = 80476433067480.

The previous prime is 81863957775583. The next prime is 81863957775623. The reversal of 81863957775599 is 99557775936818.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81863957775599 - 2⁴ = 81863957775583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81863957772599) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 693762353972 + ... + 693762354089.

It is an arithmetic number, because the mean of its divisors is an integer number (20812870620930).

Almost surely, 2^{81863957775599} is an apocalyptic number.

81863957775599 is a deficient number, since it is larger than the sum of its proper divisors (1387524708121).

81863957775599 is a wasteful number, since it uses less digits than its factorization.

81863957775599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1387524708120.

The product of its digits is 36006768000, while the sum is 89.

The spelling of 81863957775599 in words is "eighty-one trillion, eight hundred sixty-three billion, nine hundred fifty-seven million, seven hundred seventy-five thousand, five hundred ninety-nine".