21560335440 has 320 divisors, whose sum is σ = 79149934080. Its totient is φ = 4752506880.

The previous prime is 21560335409. The next prime is 21560335441. The reversal of 21560335440 is 4453306512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21560335441) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6128562 + ... + 6132078.

It is an arithmetic number, because the mean of its divisors is an integer number (247343544).

Almost surely, 2^21560335440 is an apocalyptic number.

21560335440 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 21560335440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39574967040).

21560335440 is an abundant number, since it is smaller than the sum of its proper divisors (57589598640).

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

21560335440 is a wasteful number, since it uses less digits than its factorization.

21560335440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3670 (or 3664 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 33.

The spelling of 21560335440 in words is "twenty-one billion, five hundred sixty million, three hundred thirty-five thousand, four hundred forty".