77999991331015 has 16 divisors (see below), whose sum is σ = 100853350516800. Its totient is φ = 57569501187072.

The previous prime is 77999991331001. The next prime is 77999991331021. The reversal of 77999991331015 is 51013319999977.

It is a cyclic number.

It is not a de Polignac number, because 77999991331015 - 2⁵ = 77999991330983 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 317505555 + ... + 317751124.

It is an arithmetic number, because the mean of its divisors is an integer number (6303334407300).

Almost surely, 2^{77999991331015} is an apocalyptic number.

77999991331015 is a deficient number, since it is larger than the sum of its proper divisors (22853359185785).

77999991331015 is a wasteful number, since it uses less digits than its factorization.

77999991331015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635258586.

The product of its (nonzero) digits is 130203045, while the sum is 73.

The spelling of 77999991331015 in words is "seventy-seven trillion, nine hundred ninety-nine billion, nine hundred ninety-one million, three hundred thirty-one thousand, fifteen".