77991137863 has 4 divisors (see below), whose sum is σ = 78226760968. Its totient is φ = 77755514760.

The previous prime is 77991137837. The next prime is 77991137879. The reversal of 77991137863 is 36873119977.

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 77991137863 - 2⁵ = 77991137831 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 (77991137563) 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, 117811056 + ... + 117811717.

It is an arithmetic number, because the mean of its divisors is an integer number (19556690242).

Almost surely, 2^77991137863 is an apocalyptic number.

77991137863 is a deficient number, since it is larger than the sum of its proper divisors (235623105).

77991137863 is a wasteful number, since it uses less digits than its factorization.

77991137863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235623104.

The product of its digits is 12002256, while the sum is 61.

The spelling of 77991137863 in words is "seventy-seven billion, nine hundred ninety-one million, one hundred thirty-seven thousand, eight hundred sixty-three".