18397690957 has 2 divisors, whose sum is σ = 18397690958. Its totient is φ = 18397690956.

The previous prime is 18397690933. The next prime is 18397690979. The reversal of 18397690957 is 75909679381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13617489636 + 4780201321 = 116694^2 + 69139^2 .

It is an emirp because it is prime and its reverse (75909679381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18397690957 - 2¹⁵ = 18397658189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18397690457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9198845478 + 9198845479.

It is an arithmetic number, because the mean of its divisors is an integer number (9198845479).

Almost surely, 2^18397690957 is an apocalyptic number.

It is an amenable number.

18397690957 is a deficient number, since it is larger than the sum of its proper divisors (1).

18397690957 is an equidigital number, since it uses as much as digits as its factorization.

18397690957 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25719120, while the sum is 64.

The spelling of 18397690957 in words is "eighteen billion, three hundred ninety-seven million, six hundred ninety thousand, nine hundred fifty-seven".