18239957 has 4 divisors (see below), whose sum is σ = 18684876. Its totient is φ = 17795040.

The previous prime is 18239953. The next prime is 18239959. The reversal of 18239957 is 75993281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7540516 + 10699441 = 2746^2 + 3271^2 .

It is a cyclic number.

It is not a de Polignac number, because 18239957 - 2² = 18239953 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18239953) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222398 + ... + 222479.

It is an arithmetic number, because the mean of its divisors is an integer number (4671219).

Almost surely, 2^18239957 is an apocalyptic number.

It is an amenable number.

18239957 is a deficient number, since it is larger than the sum of its proper divisors (444919).

18239957 is an equidigital number, since it uses as much as digits as its factorization.

18239957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444918.

The product of its digits is 136080, while the sum is 44.

The square root of 18239957 is about 4270.8262666608. The cubic root of 18239957 is about 263.2335677555.

The spelling of 18239957 in words is "eighteen million, two hundred thirty-nine thousand, nine hundred fifty-seven".