991951084375 has 12 divisors (see below), whose sum is σ = 1239859503288. Its totient is φ = 793560865000.

The previous prime is 991951084363. The next prime is 991951084393. The reversal of 991951084375 is 573480159199.

It is not a de Polignac number, because 991951084375 - 2¹⁵ = 991951051607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 158709049 + ... + 158715298.

It is an arithmetic number, because the mean of its divisors is an integer number (103321625274).

Almost surely, 2^991951084375 is an apocalyptic number.

991951084375 is a deficient number, since it is larger than the sum of its proper divisors (247908418913).

991951084375 is an frugal number, since it uses more digits than its factorization.

991951084375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317424372 (or 317424352 counting only the distinct ones).

The product of its (nonzero) digits is 12247200, while the sum is 61.

The spelling of 991951084375 in words is "nine hundred ninety-one billion, nine hundred fifty-one million, eighty-four thousand, three hundred seventy-five".