21663452 has 12 divisors (see below), whose sum is σ = 37943640. Its totient is φ = 10822416.

The previous prime is 21663437. The next prime is 21663497. The reversal of 21663452 is 25436612.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 7874 + ... + 10262.

It is an arithmetic number, because the mean of its divisors is an integer number (3161970).

Almost surely, 2^21663452 is an apocalyptic number.

It is an amenable number.

21663452 is a deficient number, since it is larger than the sum of its proper divisors (16280188).

21663452 is a wasteful number, since it uses less digits than its factorization.

21663452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4660 (or 4658 counting only the distinct ones).

The product of its digits is 8640, while the sum is 29.

The square root of 21663452 is about 4654.4013578547. The cubic root of 21663452 is about 278.7677653621.

The spelling of 21663452 in words is "twenty-one million, six hundred sixty-three thousand, four hundred fifty-two".