20939617 has 4 divisors (see below), whose sum is σ = 20950020. Its totient is φ = 20929216.

The previous prime is 20939609. The next prime is 20939621. The reversal of 20939617 is 71693902.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 17438976 + 3500641 = 4176^2 + 1871^2 .

It is a cyclic number.

It is not a de Polignac number, because 20939617 - 2³ = 20939609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20939627) 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, 1108 + ... + 6565.

It is an arithmetic number, because the mean of its divisors is an integer number (5237505).

Almost surely, 2^20939617 is an apocalyptic number.

It is an amenable number.

20939617 is a deficient number, since it is larger than the sum of its proper divisors (10403).

20939617 is an equidigital number, since it uses as much as digits as its factorization.

20939617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10402.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 20939617 is about 4575.9826267153. The cubic root of 20939617 is about 275.6277318508.

The spelling of 20939617 in words is "twenty million, nine hundred thirty-nine thousand, six hundred seventeen".