21807397560 has 256 divisors, whose sum is σ = 73766246400. Its totient is φ = 5117257728.

The previous prime is 21807397517. The next prime is 21807397589. The reversal of 21807397560 is 6579370812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12880074 + ... + 12881766.

It is an arithmetic number, because the mean of its divisors is an integer number (288149400).

Almost surely, 2^21807397560 is an apocalyptic number.

21807397560 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 21807397560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36883123200).

21807397560 is an abundant number, since it is smaller than the sum of its proper divisors (51958848840).

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

21807397560 is a wasteful number, since it uses less digits than its factorization.

21807397560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2102 (or 2098 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 48.

The spelling of 21807397560 in words is "twenty-one billion, eight hundred seven million, three hundred ninety-seven thousand, five hundred sixty".