18157638 has 16 divisors (see below), whose sum is σ = 36368640. Its totient is φ = 6043656.

The previous prime is 18157637. The next prime is 18157669. The reversal of 18157638 is 83675181.

It is a junction number, because it is equal to n+sod(n) for n = 18157596 and 18157605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18157637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3231 + ... + 6837.

It is an arithmetic number, because the mean of its divisors is an integer number (2273040).

Almost surely, 2^18157638 is an apocalyptic number.

18157638 is an abundant number, since it is smaller than the sum of its proper divisors (18211002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18157638 is a wasteful number, since it uses less digits than its factorization.

18157638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4451.

The product of its digits is 40320, while the sum is 39.

The square root of 18157638 is about 4261.1780061387. The cubic root of 18157638 is about 262.8369695169.

It can be divided in two parts, 1815 and 7638, that added together give a triangular number (9453 = T₁₃₇).

The spelling of 18157638 in words is "eighteen million, one hundred fifty-seven thousand, six hundred thirty-eight".