21260865400 has 72 divisors (see below), whose sum is σ = 49674298320. Its totient is φ = 8462777920.

The previous prime is 21260865389. The next prime is 21260865421. The reversal of 21260865400 is 456806212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 10304769 + ... + 10306831.

It is an arithmetic number, because the mean of its divisors is an integer number (689920810).

Almost surely, 2^21260865400 is an apocalyptic number.

21260865400 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 21260865400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24837149160).

21260865400 is an abundant number, since it is smaller than the sum of its proper divisors (28413432920).

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

21260865400 is a wasteful number, since it uses less digits than its factorization.

21260865400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2533 (or 2297 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

The spelling of 21260865400 in words is "twenty-one billion, two hundred sixty million, eight hundred sixty-five thousand, four hundred".