991577084399 has 32 divisors (see below), whose sum is σ = 1103929344000. Its totient is φ = 883039212000.

The previous prime is 991577084341. The next prime is 991577084431. The reversal of 991577084399 is 993480775199.

It is not a de Polignac number, because 991577084399 - 2¹⁶ = 991577018863 is a prime.

It is a super-2 number, since 2×991577084399² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991577081399) 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, 347798324 + ... + 347801174.

It is an arithmetic number, because the mean of its divisors is an integer number (34497792000).

Almost surely, 2^991577084399 is an apocalyptic number.

991577084399 is a deficient number, since it is larger than the sum of its proper divisors (112352259601).

991577084399 is a wasteful number, since it uses less digits than its factorization.

991577084399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4619.

The product of its (nonzero) digits is 154314720, while the sum is 71.

The spelling of 991577084399 in words is "nine hundred ninety-one billion, five hundred seventy-seven million, eighty-four thousand, three hundred ninety-nine".