990251331091 has 16 divisors (see below), whose sum is σ = 1088466385248. Its totient is φ = 893424448000.

The previous prime is 990251331053. The next prime is 990251331143. The reversal of 990251331091 is 190133152099.

It is a happy number.

990251331091 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 990251331091 - 2²⁵ = 990217776659 is a prime.

It is not an unprimeable number, because it can be changed into a prime (990251331001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 299181 + ... + 1438753.

It is an arithmetic number, because the mean of its divisors is an integer number (68029149078).

Almost surely, 2^990251331091 is an apocalyptic number.

990251331091 is a deficient number, since it is larger than the sum of its proper divisors (98215054157).

990251331091 is a wasteful number, since it uses less digits than its factorization.

990251331091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1140182.

The product of its (nonzero) digits is 65610, while the sum is 43.

The spelling of 990251331091 in words is "nine hundred ninety billion, two hundred fifty-one million, three hundred thirty-one thousand, ninety-one".