18766491431 has 2 divisors, whose sum is σ = 18766491432. Its totient is φ = 18766491430.

The previous prime is 18766491409. The next prime is 18766491439. The reversal of 18766491431 is 13419466781.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18766491431 is a prime.

It is a super-2 number, since 2×18766491431² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18766491431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18766491439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9383245715 + 9383245716.

It is an arithmetic number, because the mean of its divisors is an integer number (9383245716).

Almost surely, 2^18766491431 is an apocalyptic number.

18766491431 is a deficient number, since it is larger than the sum of its proper divisors (1).

18766491431 is an equidigital number, since it uses as much as digits as its factorization.

18766491431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 50.

The spelling of 18766491431 in words is "eighteen billion, seven hundred sixty-six million, four hundred ninety-one thousand, four hundred thirty-one".