18507857 has 2 divisors, whose sum is σ = 18507858. Its totient is φ = 18507856.

The previous prime is 18507833. The next prime is 18507859. The reversal of 18507857 is 75870581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17505856 + 1002001 = 4184^2 + 1001^2 .

It is an emirp because it is prime and its reverse (75870581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18507857 - 2¹⁰ = 18506833 is a prime.

Together with 18507859, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18507859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9253928 + 9253929.

It is an arithmetic number, because the mean of its divisors is an integer number (9253929).

Almost surely, 2^18507857 is an apocalyptic number.

It is an amenable number.

18507857 is a deficient number, since it is larger than the sum of its proper divisors (1).

18507857 is an equidigital number, since it uses as much as digits as its factorization.

18507857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 78400, while the sum is 41.

The square root of 18507857 is about 4302.0758942631. The cubic root of 18507857 is about 264.5160599309.

The spelling of 18507857 in words is "eighteen million, five hundred seven thousand, eight hundred fifty-seven".