991125622928 has 80 divisors (see below), whose sum is σ = 2266436176896. Its totient is φ = 410883356160.

The previous prime is 991125622909. The next prime is 991125622933. The reversal of 991125622928 is 829226521199.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (56).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7899050 + ... + 8023542.

Almost surely, 2^991125622928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991125622928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1133218088448).

991125622928 is an abundant number, since it is smaller than the sum of its proper divisors (1275310553968).

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

991125622928 is a wasteful number, since it uses less digits than its factorization.

991125622928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126832 (or 126826 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 56.

The spelling of 991125622928 in words is "nine hundred ninety-one billion, one hundred twenty-five million, six hundred twenty-two thousand, nine hundred twenty-eight".