21629568 has 128 divisors (see below), whose sum is σ = 62668800. Its totient is φ = 6589440.

The previous prime is 21629561. The next prime is 21629579. The reversal of 21629568 is 86592612.

It is a tau number, because it is divible by the number of its divisors (128).

It is not an unprimeable number, because it can be changed into a prime (21629561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 273753 + ... + 273831.

It is an arithmetic number, because the mean of its divisors is an integer number (489600).

Almost surely, 2^21629568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21629568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31334400).

21629568 is an abundant number, since it is smaller than the sum of its proper divisors (41039232).

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

21629568 is a wasteful number, since it uses less digits than its factorization.

21629568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 138 counting only the distinct ones).

The product of its digits is 51840, while the sum is 39.

The square root of 21629568 is about 4650.7599379026. The cubic root of 21629568 is about 278.6223484640.

The spelling of 21629568 in words is "twenty-one million, six hundred twenty-nine thousand, five hundred sixty-eight".