18520139 has 6 divisors (see below), whose sum is σ = 20356980. Its totient is φ = 16836380.

The previous prime is 18520111. The next prime is 18520147. The reversal of 18520139 is 93102581.

It is not a de Polignac number, because 18520139 - 2¹⁶ = 18454603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18520109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 76409 + ... + 76650.

It is an arithmetic number, because the mean of its divisors is an integer number (3392830).

Almost surely, 2^18520139 is an apocalyptic number.

18520139 is a deficient number, since it is larger than the sum of its proper divisors (1836841).

18520139 is a wasteful number, since it uses less digits than its factorization.

18520139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153081 (or 153070 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 18520139 is about 4303.5031079343. The cubic root of 18520139 is about 264.5745588316.

The spelling of 18520139 in words is "eighteen million, five hundred twenty thousand, one hundred thirty-nine".