21629660 has 48 divisors (see below), whose sum is σ = 51057216. Its totient is φ = 7636992.

The previous prime is 21629617. The next prime is 21629687. The reversal of 21629660 is 6692612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4172 + ... + 7788.

It is an arithmetic number, because the mean of its divisors is an integer number (1063692).

Almost surely, 2^21629660 is an apocalyptic number.

21629660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21629660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25528608).

21629660 is an abundant number, since it is smaller than the sum of its proper divisors (29427556).

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

21629660 is a wasteful number, since it uses less digits than its factorization.

21629660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3662 (or 3660 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 21629660 is about 4650.7698287488. The cubic root of 21629660 is about 278.6227434976.

The spelling of 21629660 in words is "twenty-one million, six hundred twenty-nine thousand, six hundred sixty".