21583478280 has 256 divisors, whose sum is σ = 79913433600. Its totient is φ = 4541276160.

The previous prime is 21583478261. The next prime is 21583478309. The reversal of 21583478280 is 8287438512.

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, 4245340 + ... + 4250420.

It is an arithmetic number, because the mean of its divisors is an integer number (312161850).

Almost surely, 2^21583478280 is an apocalyptic number.

21583478280 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 21583478280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39956716800).

21583478280 is an abundant number, since it is smaller than the sum of its proper divisors (58329955320).

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

21583478280 is a wasteful number, since it uses less digits than its factorization.

21583478280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5504 (or 5500 counting only the distinct ones).

The product of its (nonzero) digits is 860160, while the sum is 48.

The spelling of 21583478280 in words is "twenty-one billion, five hundred eighty-three million, four hundred seventy-eight thousand, two hundred eighty".