18257389 has 2 divisors, whose sum is σ = 18257390. Its totient is φ = 18257388.

The previous prime is 18257381. The next prime is 18257399. The reversal of 18257389 is 98375281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15468489 + 2788900 = 3933^2 + 1670^2 .

It is an emirp because it is prime and its reverse (98375281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18257389 - 2³ = 18257381 is a prime.

It is a super-4 number, since 4×18257389⁴ (a number of 30 digits) contains 4444 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18257381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9128694 + 9128695.

It is an arithmetic number, because the mean of its divisors is an integer number (9128695).

Almost surely, 2^18257389 is an apocalyptic number.

It is an amenable number.

18257389 is a deficient number, since it is larger than the sum of its proper divisors (1).

18257389 is an equidigital number, since it uses as much as digits as its factorization.

18257389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 43.

The square root of 18257389 is about 4272.8666021770. The cubic root of 18257389 is about 263.3173988471.

The spelling of 18257389 in words is "eighteen million, two hundred fifty-seven thousand, three hundred eighty-nine".