21632563 has 2 divisors, whose sum is σ = 21632564. Its totient is φ = 21632562.

The previous prime is 21632557. The next prime is 21632587. The reversal of 21632563 is 36523612.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21632563 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21632503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10816281 + 10816282.

It is an arithmetic number, because the mean of its divisors is an integer number (10816282).

Almost surely, 2^21632563 is an apocalyptic number.

21632563 is a deficient number, since it is larger than the sum of its proper divisors (1).

21632563 is an equidigital number, since it uses as much as digits as its factorization.

21632563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 28.

The square root of 21632563 is about 4651.0819171457. The cubic root of 21632563 is about 278.6352079506.

The spelling of 21632563 in words is "twenty-one million, six hundred thirty-two thousand, five hundred sixty-three".