21487960 has 96 divisors (see below), whose sum is σ = 55051920. Its totient is φ = 7499520.

The previous prime is 21487951. The next prime is 21487981. The reversal of 21487960 is 6978412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 499699 + ... + 499741.

Almost surely, 2^21487960 is an apocalyptic number.

21487960 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 21487960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27525960).

21487960 is an abundant number, since it is smaller than the sum of its proper divisors (33563960).

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

21487960 is a wasteful number, since it uses less digits than its factorization.

21487960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 21487960 is about 4635.5107593446. The cubic root of 21487960 is about 278.0129731882.

The spelling of 21487960 in words is "twenty-one million, four hundred eighty-seven thousand, nine hundred sixty".