18631957 has 2 divisors, whose sum is σ = 18631958. Its totient is φ = 18631956.

The previous prime is 18631939. The next prime is 18631993. The reversal of 18631957 is 75913681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16532356 + 2099601 = 4066^2 + 1449^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18631957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18631937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9315978 + 9315979.

It is an arithmetic number, because the mean of its divisors is an integer number (9315979).

Almost surely, 2^18631957 is an apocalyptic number.

It is an amenable number.

18631957 is a deficient number, since it is larger than the sum of its proper divisors (1).

18631957 is an equidigital number, since it uses as much as digits as its factorization.

18631957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45360, while the sum is 40.

The square root of 18631957 is about 4316.4750665329. The cubic root of 18631957 is about 265.1059597625.

The spelling of 18631957 in words is "eighteen million, six hundred thirty-one thousand, nine hundred fifty-seven".