21046563 has 6 divisors (see below), whose sum is σ = 30400604. Its totient is φ = 14031036.

The previous prime is 21046549. The next prime is 21046573. The reversal of 21046563 is 36564012.

21046563 is a `hidden beast` number, since 2 + 1 + 0 + 4 + 656 + 3 = 666.

It is not a de Polignac number, because 21046563 - 2¹⁰ = 21045539 is a prime.

It is a super-2 number, since 2×21046563² = 885915628225938, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21046513) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1169245 + ... + 1169262.

Almost surely, 2^21046563 is an apocalyptic number.

21046563 is a deficient number, since it is larger than the sum of its proper divisors (9354041).

21046563 is a wasteful number, since it uses less digits than its factorization.

21046563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2338513 (or 2338510 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 21046563 is about 4587.6533216886. The cubic root of 21046563 is about 276.0961778861.

It can be divided in two parts, 21046 and 563, that added together give a square (21609 = 147²).

The spelling of 21046563 in words is "twenty-one million, forty-six thousand, five hundred sixty-three".