21452566 has 4 divisors (see below), whose sum is σ = 32178852. Its totient is φ = 10726282.

The previous prime is 21452549. The next prime is 21452567. The reversal of 21452566 is 66525412.

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

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21452567) 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 as a sum of consecutive naturals, namely, 5363140 + ... + 5363143.

It is an arithmetic number, because the mean of its divisors is an integer number (8044713).

Almost surely, 2^21452566 is an apocalyptic number.

21452566 is a deficient number, since it is larger than the sum of its proper divisors (10726286).

21452566 is a wasteful number, since it uses less digits than its factorization.

21452566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10726285.

The product of its digits is 14400, while the sum is 31.

The square root of 21452566 is about 4631.6914836807. The cubic root of 21452566 is about 277.8602458192.

Adding to 21452566 its reverse (66525412), we get a palindrome (87977978).

The spelling of 21452566 in words is "twenty-one million, four hundred fifty-two thousand, five hundred sixty-six".