18390857 has 2 divisors, whose sum is σ = 18390858. Its totient is φ = 18390856.

The previous prime is 18390851. The next prime is 18390877. The reversal of 18390857 is 75809381.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13278736 + 5112121 = 3644^2 + 2261^2 .

It is an emirp because it is prime and its reverse (75809381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18390857 - 2⁶ = 18390793 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18390851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9195428 + 9195429.

It is an arithmetic number, because the mean of its divisors is an integer number (9195429).

Almost surely, 2^18390857 is an apocalyptic number.

It is an amenable number.

18390857 is a deficient number, since it is larger than the sum of its proper divisors (1).

18390857 is an equidigital number, since it uses as much as digits as its factorization.

18390857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 41.

The square root of 18390857 is about 4288.4562490481. The cubic root of 18390857 is about 263.9574895203.

The spelling of 18390857 in words is "eighteen million, three hundred ninety thousand, eight hundred fifty-seven".