20090639 has 4 divisors (see below), whose sum is σ = 20237424. Its totient is φ = 19943856.

The previous prime is 20090627. The next prime is 20090647. The reversal of 20090639 is 93609002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93609002 = 2 ⋅46804501.

It is a cyclic number.

It is not a de Polignac number, because 20090639 - 2²⁰ = 19042063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20090659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73187 + ... + 73460.

It is an arithmetic number, because the mean of its divisors is an integer number (5059356).

Almost surely, 2^20090639 is an apocalyptic number.

20090639 is a deficient number, since it is larger than the sum of its proper divisors (146785).

20090639 is a wasteful number, since it uses less digits than its factorization.

20090639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146784.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 20090639 is about 4482.2582478032. The cubic root of 20090639 is about 271.8511972643.

The spelling of 20090639 in words is "twenty million, ninety thousand, six hundred thirty-nine".