20039491 has 4 divisors (see below), whose sum is σ = 20183800. Its totient is φ = 19895184.

The previous prime is 20039479. The next prime is 20039497. The reversal of 20039491 is 19493002.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19493002 = 2 ⋅9746501.

It is a cyclic number.

It is not a de Polignac number, because 20039491 - 2⁷ = 20039363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20039497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71946 + ... + 72223.

It is an arithmetic number, because the mean of its divisors is an integer number (5045950).

Almost surely, 2^20039491 is an apocalyptic number.

20039491 is a deficient number, since it is larger than the sum of its proper divisors (144309).

20039491 is a wasteful number, since it uses less digits than its factorization.

20039491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144308.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 20039491 is about 4476.5490056516. The cubic root of 20039491 is about 271.6203026418.

The spelling of 20039491 in words is "twenty million, thirty-nine thousand, four hundred ninety-one".