21629520 has 120 divisors (see below), whose sum is σ = 79271712. Its totient is φ = 5241600.

The previous prime is 21629519. The next prime is 21629527. The reversal of 21629520 is 2592612.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×21629520² = 935672270860800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21629527) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6555 + ... + 9285.

Almost surely, 2^21629520 is an apocalyptic number.

21629520 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 21629520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39635856).

21629520 is an abundant number, since it is smaller than the sum of its proper divisors (57642192).

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

21629520 is a wasteful number, since it uses less digits than its factorization.

21629520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2761 (or 2752 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 21629520 is about 4650.7547774528. The cubic root of 21629520 is about 278.6221423590.

The spelling of 21629520 in words is "twenty-one million, six hundred twenty-nine thousand, five hundred twenty".