16991365231 has 4 divisors (see below), whose sum is σ = 17269912264. Its totient is φ = 16712818200.

The previous prime is 16991365211. The next prime is 16991365243. The reversal of 16991365231 is 13256319961.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 16991365231 - 2⁵ = 16991365199 is a prime.

It is a super-2 number, since 2×16991365231² (a number of 21 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 (16991365211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 139273425 + ... + 139273546.

It is an arithmetic number, because the mean of its divisors is an integer number (4317478066).

Almost surely, 2^16991365231 is an apocalyptic number.

16991365231 is a deficient number, since it is larger than the sum of its proper divisors (278547033).

16991365231 is an equidigital number, since it uses as much as digits as its factorization.

16991365231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278547032.

The product of its digits is 262440, while the sum is 46.

The spelling of 16991365231 in words is "sixteen billion, nine hundred ninety-one million, three hundred sixty-five thousand, two hundred thirty-one".