18731585657 has 2 divisors, whose sum is σ = 18731585658. Its totient is φ = 18731585656.

The previous prime is 18731585633. The next prime is 18731585683. The reversal of 18731585657 is 75658513781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18455494201 + 276091456 = 135851^2 + 16616^2 .

It is a cyclic number.

It is not a de Polignac number, because 18731585657 - 2⁸ = 18731585401 is a prime.

It is not a weakly prime, because it can be changed into another prime (18731585357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9365792828 + 9365792829.

It is an arithmetic number, because the mean of its divisors is an integer number (9365792829).

Almost surely, 2^18731585657 is an apocalyptic number.

It is an amenable number.

18731585657 is a deficient number, since it is larger than the sum of its proper divisors (1).

18731585657 is an equidigital number, since it uses as much as digits as its factorization.

18731585657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056000, while the sum is 56.

The spelling of 18731585657 in words is "eighteen billion, seven hundred thirty-one million, five hundred eighty-five thousand, six hundred fifty-seven".