21529040 has 80 divisors (see below), whose sum is σ = 54663168. Its totient is φ = 7838208.

The previous prime is 21529019. The next prime is 21529051. The reversal of 21529040 is 4092512.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 21528997 and 21529015.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 131999 + ... + 132161.

Almost surely, 2^21529040 is an apocalyptic number.

21529040 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 21529040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27331584).

21529040 is an abundant number, since it is smaller than the sum of its proper divisors (33134128).

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

21529040 is a wasteful number, since it uses less digits than its factorization.

21529040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316 (or 310 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21529040 is about 4639.9396547800. The cubic root of 21529040 is about 278.1900258680.

The spelling of 21529040 in words is "twenty-one million, five hundred twenty-nine thousand, forty".