21775445520 has 320 divisors, whose sum is σ = 75598375680. Its totient is φ = 5152702464.

The previous prime is 21775445519. The next prime is 21775445533. The reversal of 21775445520 is 2554457712.

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, 19922094 + ... + 19923186.

It is an arithmetic number, because the mean of its divisors is an integer number (236244924).

Almost surely, 2^21775445520 is an apocalyptic number.

21775445520 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 21775445520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37799187840).

21775445520 is an abundant number, since it is smaller than the sum of its proper divisors (53822930160).

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

21775445520 is a wasteful number, since it uses less digits than its factorization.

21775445520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1402 (or 1396 counting only the distinct ones).

The product of its (nonzero) digits is 392000, while the sum is 42.

The spelling of 21775445520 in words is "twenty-one billion, seven hundred seventy-five million, four hundred forty-five thousand, five hundred twenty".