18139522 has 4 divisors (see below), whose sum is σ = 27209286. Its totient is φ = 9069760.

The previous prime is 18139501. The next prime is 18139523. The reversal of 18139522 is 22593181.

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

It can be written as a sum of positive squares in only one way, i.e., 18139081 + 441 = 4259^2 + 21^2 .

It is not an unprimeable number, because it can be changed into a prime (18139523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4534879 + ... + 4534882.

Almost surely, 2^18139522 is an apocalyptic number.

18139522 is a deficient number, since it is larger than the sum of its proper divisors (9069764).

18139522 is an equidigital number, since it uses as much as digits as its factorization.

18139522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9069763.

The product of its digits is 4320, while the sum is 31.

The square root of 18139522 is about 4259.0517724019. The cubic root of 18139522 is about 262.7495290146.

The spelling of 18139522 in words is "eighteen million, one hundred thirty-nine thousand, five hundred twenty-two".