21529880 has 16 divisors (see below), whose sum is σ = 48442320. Its totient is φ = 8611936.

The previous prime is 21529873. The next prime is 21529883. The reversal of 21529880 is 8892512.

It is a self number, because there is not a number n which added to its sum of digits gives 21529880.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21529883) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 269084 + ... + 269163.

It is an arithmetic number, because the mean of its divisors is an integer number (3027645).

Almost surely, 2^21529880 is an apocalyptic number.

21529880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21529880 is an abundant number, since it is smaller than the sum of its proper divisors (26912440).

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

21529880 is a wasteful number, since it uses less digits than its factorization.

21529880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538258 (or 538254 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 35.

The square root of 21529880 is about 4640.0301723157. The cubic root of 21529880 is about 278.1936438739.

The spelling of 21529880 in words is "twenty-one million, five hundred twenty-nine thousand, eight hundred eighty".