21905026560 has 320 divisors, whose sum is σ = 80326287360. Its totient is φ = 5652357120.

The previous prime is 21905026523. The next prime is 21905026579. The reversal of 21905026560 is 6562050912.

21905026560 is a `hidden beast` number, since 2 + 1 + 90 + 5 + 0 + 2 + 6 + 560 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

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

It is a congruent number.

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, 2137609 + ... + 2147831.

It is an arithmetic number, because the mean of its divisors is an integer number (251019648).

Almost surely, 2^21905026560 is an apocalyptic number.

21905026560 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 21905026560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40163143680).

21905026560 is an abundant number, since it is smaller than the sum of its proper divisors (58421260800).

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

21905026560 is a wasteful number, since it uses less digits than its factorization.

21905026560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10286 (or 10264 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The spelling of 21905026560 in words is "twenty-one billion, nine hundred five million, twenty-six thousand, five hundred sixty".