18618857 has 2 divisors, whose sum is σ = 18618858. Its totient is φ = 18618856.

The previous prime is 18618811. The next prime is 18618863. The reversal of 18618857 is 75881681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16556761 + 2062096 = 4069^2 + 1436^2 .

It is an emirp because it is prime and its reverse (75881681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18618857 - 2⁸ = 18618601 is a prime.

It is not a weakly prime, because it can be changed into another prime (18618877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9309428 + 9309429.

It is an arithmetic number, because the mean of its divisors is an integer number (9309429).

Almost surely, 2^18618857 is an apocalyptic number.

It is an amenable number.

18618857 is a deficient number, since it is larger than the sum of its proper divisors (1).

18618857 is an equidigital number, since it uses as much as digits as its factorization.

18618857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 107520, while the sum is 44.

The square root of 18618857 is about 4314.9573578426. The cubic root of 18618857 is about 265.0438138070.

The spelling of 18618857 in words is "eighteen million, six hundred eighteen thousand, eight hundred fifty-seven".