20646863 has 4 divisors (see below), whose sum is σ = 21733560. Its totient is φ = 19560168.

The previous prime is 20646841. The next prime is 20646877. The reversal of 20646863 is 36864602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20646863 - 2⁶ = 20646799 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 (20646833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 543320 + ... + 543357.

It is an arithmetic number, because the mean of its divisors is an integer number (5433390).

Almost surely, 2^20646863 is an apocalyptic number.

20646863 is a deficient number, since it is larger than the sum of its proper divisors (1086697).

20646863 is a wasteful number, since it uses less digits than its factorization.

20646863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1086696.

The product of its (nonzero) digits is 41472, while the sum is 35.

The square root of 20646863 is about 4543.8819306844. The cubic root of 20646863 is about 274.3371938680.

The spelling of 20646863 in words is "twenty million, six hundred forty-six thousand, eight hundred sixty-three".