21663629 has 16 divisors (see below), whose sum is σ = 24729600. Its totient is φ = 18812736.

The previous prime is 21663623. The next prime is 21663647. The reversal of 21663629 is 92636612.

It is not a de Polignac number, because 21663629 - 2⁸ = 21663373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21663623) 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, 56372 + ... + 56754.

It is an arithmetic number, because the mean of its divisors is an integer number (1545600).

Almost surely, 2^21663629 is an apocalyptic number.

It is an amenable number.

21663629 is a deficient number, since it is larger than the sum of its proper divisors (3065971).

21663629 is a wasteful number, since it uses less digits than its factorization.

21663629 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644.

The product of its digits is 23328, while the sum is 35.

The square root of 21663629 is about 4654.4203720764. The cubic root of 21663629 is about 278.7685245788.

The spelling of 21663629 in words is "twenty-one million, six hundred sixty-three thousand, six hundred twenty-nine".