21466563 has 16 divisors (see below), whose sum is σ = 30420000. Its totient is φ = 13418496.

The previous prime is 21466559. The next prime is 21466573. The reversal of 21466563 is 36566412.

It is not a de Polignac number, because 21466563 - 2² = 21466559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21466513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16563 + ... + 17811.

It is an arithmetic number, because the mean of its divisors is an integer number (1901250).

Almost surely, 2^21466563 is an apocalyptic number.

21466563 is a deficient number, since it is larger than the sum of its proper divisors (8953437).

21466563 is a wasteful number, since it uses less digits than its factorization.

21466563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1606.

The product of its digits is 25920, while the sum is 33.

The square root of 21466563 is about 4633.2022403517. The cubic root of 21466563 is about 277.9206638335.

The spelling of 21466563 in words is "twenty-one million, four hundred sixty-six thousand, five hundred sixty-three".