21285588240 has 600 divisors, whose sum is σ = 88054274880. Its totient is φ = 4749083136.

The previous prime is 21285588221. The next prime is 21285588251. The reversal of 21285588240 is 4288558212.

21285588240 is a `hidden beast` number, since 2 + 1 + 28 + 5 + 588 + 2 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 13652581 + ... + 13654139.

Almost surely, 2^21285588240 is an apocalyptic number.

21285588240 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 21285588240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44027137440).

21285588240 is an abundant number, since it is smaller than the sum of its proper divisors (66768686640).

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

21285588240 is a wasteful number, since it uses less digits than its factorization.

21285588240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1641 (or 1619 counting only the distinct ones).

The product of its (nonzero) digits is 409600, while the sum is 45.

The spelling of 21285588240 in words is "twenty-one billion, two hundred eighty-five million, five hundred eighty-eight thousand, two hundred forty".