18157109 has 2 divisors, whose sum is σ = 18157110. Its totient is φ = 18157108.

The previous prime is 18157099. The next prime is 18157133. The reversal of 18157109 is 90175181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16834609 + 1322500 = 4103^2 + 1150^2 .

It is a cyclic number.

It is not a de Polignac number, because 18157109 - 2¹⁶ = 18091573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18157159) 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, 9078554 + 9078555.

It is an arithmetic number, because the mean of its divisors is an integer number (9078555).

Almost surely, 2^18157109 is an apocalyptic number.

It is an amenable number.

18157109 is a deficient number, since it is larger than the sum of its proper divisors (1).

18157109 is an equidigital number, since it uses as much as digits as its factorization.

18157109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 32.

The square root of 18157109 is about 4261.1159336493. The cubic root of 18157109 is about 262.8344170170.

The spelling of 18157109 in words is "eighteen million, one hundred fifty-seven thousand, one hundred nine".