20643268 has 24 divisors (see below), whose sum is σ = 37189152. Its totient is φ = 10020864.

The previous prime is 20643257. The next prime is 20643269. The reversal of 20643268 is 86234602.

It is a super-2 number, since 2×20643268² = 852289027439648, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20643269) 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, 43971 + ... + 44437.

It is an arithmetic number, because the mean of its divisors is an integer number (1549548).

Almost surely, 2^20643268 is an apocalyptic number.

It is an amenable number.

20643268 is a deficient number, since it is larger than the sum of its proper divisors (16545884).

20643268 is a wasteful number, since it uses less digits than its factorization.

20643268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771 (or 769 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 20643268 is about 4543.4863265999. The cubic root of 20643268 is about 274.3212705538.

The spelling of 20643268 in words is "twenty million, six hundred forty-three thousand, two hundred sixty-eight".