18311309957 has 2 divisors, whose sum is σ = 18311309958. Its totient is φ = 18311309956.

The previous prime is 18311309923. The next prime is 18311309987. The reversal of 18311309957 is 75990311381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18236071681 + 75238276 = 135041^2 + 8674^2 .

It is a cyclic number.

It is not a de Polignac number, because 18311309957 - 2⁶ = 18311309893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18311309987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9155654978 + 9155654979.

It is an arithmetic number, because the mean of its divisors is an integer number (9155654979).

Almost surely, 2^18311309957 is an apocalyptic number.

It is an amenable number.

18311309957 is a deficient number, since it is larger than the sum of its proper divisors (1).

18311309957 is an equidigital number, since it uses as much as digits as its factorization.

18311309957 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 204120, while the sum is 47.

The spelling of 18311309957 in words is "eighteen billion, three hundred eleven million, three hundred nine thousand, nine hundred fifty-seven".