20764639 has 8 divisors (see below), whose sum is σ = 23823360. Its totient is φ = 17729016.

The previous prime is 20764619. The next prime is 20764651. The reversal of 20764639 is 93646702.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20764639 - 2⁹ = 20764127 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20764598 and 20764607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20764619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3799 + ... + 7480.

It is an arithmetic number, because the mean of its divisors is an integer number (2977920).

Almost surely, 2^20764639 is an apocalyptic number.

20764639 is a deficient number, since it is larger than the sum of its proper divisors (3058721).

20764639 is a wasteful number, since it uses less digits than its factorization.

20764639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11549.

The product of its (nonzero) digits is 54432, while the sum is 37.

The square root of 20764639 is about 4556.8233452703. The cubic root of 20764639 is about 274.8578394708.

It can be divided in two parts, 207 and 64639, that added together give a palindrome (64846).

The spelling of 20764639 in words is "twenty million, seven hundred sixty-four thousand, six hundred thirty-nine".