991168354431 has 12 divisors (see below), whose sum is σ = 1484713090952. Its totient is φ = 660778902792.

The previous prime is 991168354427. The next prime is 991168354469. The reversal of 991168354431 is 134453861199.

991168354431 is a `hidden beast` number, since 9 + 9 + 1 + 1 + 68 + 3 + 544 + 31 = 666.

It is not a de Polignac number, because 991168354431 - 2² = 991168354427 is a prime.

It is a super-2 number, since 2×991168354431² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991168358431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2039440816 + ... + 2039441301.

Almost surely, 2^991168354431 is an apocalyptic number.

991168354431 is a deficient number, since it is larger than the sum of its proper divisors (493544736521).

991168354431 is an equidigital number, since it uses as much as digits as its factorization.

991168354431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4078882132 (or 4078882120 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 54.

The spelling of 991168354431 in words is "nine hundred ninety-one billion, one hundred sixty-eight million, three hundred fifty-four thousand, four hundred thirty-one".