20643404 has 6 divisors (see below), whose sum is σ = 36125964. Its totient is φ = 10321700.

The previous prime is 20643379. The next prime is 20643407. The reversal of 20643404 is 40434602.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20643404.

It is not an unprimeable number, because it can be changed into a prime (20643407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2580422 + ... + 2580429.

It is an arithmetic number, because the mean of its divisors is an integer number (6020994).

Almost surely, 2^20643404 is an apocalyptic number.

It is an amenable number.

20643404 is a deficient number, since it is larger than the sum of its proper divisors (15482560).

20643404 is a wasteful number, since it uses less digits than its factorization.

20643404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5160855 (or 5160853 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 23.

The square root of 20643404 is about 4543.5012930558. The cubic root of 20643404 is about 274.3218729716.

The spelling of 20643404 in words is "twenty million, six hundred forty-three thousand, four hundred four".