18381357 has 16 divisors (see below), whose sum is σ = 28111360. Its totient is φ = 11858400.

The previous prime is 18381353. The next prime is 18381359. The reversal of 18381357 is 75318381.

It is not a de Polignac number, because 18381357 - 2² = 18381353 is a prime.

It is a super-2 number, since 2×18381357² = 675748570322898, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18381353) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10144 + ... + 11817.

It is an arithmetic number, because the mean of its divisors is an integer number (1756960).

Almost surely, 2^18381357 is an apocalyptic number.

It is an amenable number.

18381357 is a deficient number, since it is larger than the sum of its proper divisors (9730003).

18381357 is a wasteful number, since it uses less digits than its factorization.

18381357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22001 (or 21995 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 18381357 is about 4287.3484812877. The cubic root of 18381357 is about 263.9120316414.

The spelling of 18381357 in words is "eighteen million, three hundred eighty-one thousand, three hundred fifty-seven".