18115957 has 4 divisors (see below), whose sum is σ = 18124780. Its totient is φ = 18107136.

The previous prime is 18115939. The next prime is 18115967. The reversal of 18115957 is 75951181.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12327121 + 5788836 = 3511^2 + 2406^2 .

It is a cyclic number.

It is not a de Polignac number, because 18115957 - 2¹⁹ = 17591669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18115907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 469 + ... + 6037.

It is an arithmetic number, because the mean of its divisors is an integer number (4531195).

Almost surely, 2^18115957 is an apocalyptic number.

It is an amenable number.

18115957 is a deficient number, since it is larger than the sum of its proper divisors (8823).

18115957 is an equidigital number, since it uses as much as digits as its factorization.

18115957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8822.

The product of its digits is 12600, while the sum is 37.

The square root of 18115957 is about 4256.2844124894. The cubic root of 18115957 is about 262.6357006607.

The spelling of 18115957 in words is "eighteen million, one hundred fifteen thousand, nine hundred fifty-seven".