21540224808 has 128 divisors (see below), whose sum is σ = 61823865600. Its totient is φ = 6945120000.

The previous prime is 21540224749. The next prime is 21540224813. The reversal of 21540224808 is 80842204512.

21540224808 is a `hidden beast` number, since 2 + 1 + 5 + 402 + 248 + 0 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 799558 + ... + 826058.

It is an arithmetic number, because the mean of its divisors is an integer number (482998950).

Almost surely, 2^21540224808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21540224808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30911932800).

21540224808 is an abundant number, since it is smaller than the sum of its proper divisors (40283640792).

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

21540224808 is a wasteful number, since it uses less digits than its factorization.

21540224808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26640 (or 26630 counting only the distinct ones).

The product of its (nonzero) digits is 40960, while the sum is 36.

The spelling of 21540224808 in words is "twenty-one billion, five hundred forty million, two hundred twenty-four thousand, eight hundred eight".