20009138 has 6 divisors (see below), whose sum is σ = 30023199. Its totient is φ = 10001406.

The previous prime is 20009137. The next prime is 20009173. The reversal of 20009138 is 83190002.

It can be written as a sum of positive squares in only one way, i.e., 10004569 + 10004569 = 3163^2 + 3163^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3163.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20009137) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4745 + ... + 7907.

Almost surely, 2^20009138 is an apocalyptic number.

20009138 is a deficient number, since it is larger than the sum of its proper divisors (10014061).

20009138 is an frugal number, since it uses more digits than its factorization.

20009138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6328 (or 3165 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 20009138 is about 4473.1574977861. The cubic root of 20009138 is about 271.4830959452.

The spelling of 20009138 in words is "twenty million, nine thousand, one hundred thirty-eight".