991143569904 has 20 divisors (see below), whose sum is σ = 2560454222376. Its totient is φ = 330381189952.

The previous prime is 991143569879. The next prime is 991143569947. The reversal of 991143569904 is 409965341199.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10324412139 + ... + 10324412234.

Almost surely, 2^991143569904 is an apocalyptic number.

It is an amenable number.

991143569904 is an abundant number, since it is smaller than the sum of its proper divisors (1569310652472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991143569904 is a wasteful number, since it uses less digits than its factorization.

991143569904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20648824384 (or 20648824378 counting only the distinct ones).

The product of its (nonzero) digits is 9447840, while the sum is 60.

The spelling of 991143569904 in words is "nine hundred ninety-one billion, one hundred forty-three million, five hundred sixty-nine thousand, nine hundred four".