20639613 has 16 divisors (see below), whose sum is σ = 28339520. Its totient is φ = 13353984.

The previous prime is 20639587. The next prime is 20639623. The reversal of 20639613 is 31693602.

It is a happy number.

It is not a de Polignac number, because 20639613 - 2¹⁰ = 20638589 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 (20639623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24483 + ... + 25311.

It is an arithmetic number, because the mean of its divisors is an integer number (1771220).

Almost surely, 2^20639613 is an apocalyptic number.

It is an amenable number.

20639613 is a deficient number, since it is larger than the sum of its proper divisors (7699907).

20639613 is a wasteful number, since it uses less digits than its factorization.

20639613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1068.

The product of its (nonzero) digits is 5832, while the sum is 30.

The square root of 20639613 is about 4543.0840846280. The cubic root of 20639613 is about 274.3050795867.

The spelling of 20639613 in words is "twenty million, six hundred thirty-nine thousand, six hundred thirteen".