991455788625 has 128 divisors (see below), whose sum is σ = 1680555561984. Its totient is φ = 519045120000.

The previous prime is 991455788593. The next prime is 991455788657. The reversal of 991455788625 is 526887554199.

It is an interprime number because it is at equal distance from previous prime (991455788593) and next prime (991455788657).

It is not a de Polignac number, because 991455788625 - 2⁵ = 991455788593 is a prime.

Its product of digits (217728000) is a multiple of the sum of its prime factors (972).

It is a self number, because there is not a number n which added to its sum of digits gives 991455788625.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2808656449 + ... + 2808656801.

It is an arithmetic number, because the mean of its divisors is an integer number (13129340328).

Almost surely, 2^991455788625 is an apocalyptic number.

It is an amenable number.

991455788625 is a deficient number, since it is larger than the sum of its proper divisors (689099773359).

991455788625 is a wasteful number, since it uses less digits than its factorization.

991455788625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972 (or 962 counting only the distinct ones).

The product of its digits is 217728000, while the sum is 69.

The spelling of 991455788625 in words is "nine hundred ninety-one billion, four hundred fifty-five million, seven hundred eighty-eight thousand, six hundred twenty-five".