21409855488 has 576 divisors, whose sum is σ = 76903706880. Its totient is φ = 5598609408.

The previous prime is 21409855487. The next prime is 21409855499. The reversal of 21409855488 is 88455890412.

21409855488 is a `hidden beast` number, since 2 + 1 + 4 + 0 + 9 + 8 + 554 + 88 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21409855483) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 94316431 + ... + 94316657.

It is an arithmetic number, because the mean of its divisors is an integer number (133513380).

Almost surely, 2^21409855488 is an apocalyptic number.

21409855488 is a gapful number since it is divisible by the number (28) 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 21409855488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38451853440).

21409855488 is an abundant number, since it is smaller than the sum of its proper divisors (55493851392).

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

21409855488 is a wasteful number, since it uses less digits than its factorization.

21409855488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322 (or 299 counting only the distinct ones).

The product of its (nonzero) digits is 3686400, while the sum is 54.

The spelling of 21409855488 in words is "twenty-one billion, four hundred nine million, eight hundred fifty-five thousand, four hundred eighty-eight".