20939137 has 4 divisors (see below), whose sum is σ = 20955220. Its totient is φ = 20923056.

The previous prime is 20939123. The next prime is 20939147. The reversal of 20939137 is 73193902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73193902 = 2 ⋅36596951.

It can be written as a sum of positive squares in 2 ways, for example, as 8520561 + 12418576 = 2919^2 + 3524^2 .

It is a cyclic number.

It is not a de Polignac number, because 20939137 - 2²³ = 12550529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20939147) 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 3 ways as a sum of consecutive naturals, for example, 5898 + ... + 8755.

It is an arithmetic number, because the mean of its divisors is an integer number (5238805).

Almost surely, 2^20939137 is an apocalyptic number.

It is an amenable number.

20939137 is a deficient number, since it is larger than the sum of its proper divisors (16083).

20939137 is a wasteful number, since it uses less digits than its factorization.

20939137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16082.

The product of its (nonzero) digits is 10206, while the sum is 34.

The square root of 20939137 is about 4575.9301786631. The cubic root of 20939137 is about 275.6256257581.

The spelling of 20939137 in words is "twenty million, nine hundred thirty-nine thousand, one hundred thirty-seven".