21232566 has 24 divisors (see below), whose sum is σ = 46785960. Its totient is φ = 6957216.

The previous prime is 21232531. The next prime is 21232571. The reversal of 21232566 is 66523212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8935 + ... + 11058.

It is an arithmetic number, because the mean of its divisors is an integer number (1949415).

Almost surely, 2^21232566 is an apocalyptic number.

21232566 is an abundant number, since it is smaller than the sum of its proper divisors (25553394).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21232566 is a wasteful number, since it uses less digits than its factorization.

21232566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20060 (or 20057 counting only the distinct ones).

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

The square root of 21232566 is about 4607.8808578348. The cubic root of 21232566 is about 276.9071443469.

Adding to 21232566 its reverse (66523212), we get a palindrome (87755778).

The spelling of 21232566 in words is "twenty-one million, two hundred thirty-two thousand, five hundred sixty-six".