21526221304 has 128 divisors (see below), whose sum is σ = 51925017600. Its totient is φ = 8143718400.

The previous prime is 21526221259. The next prime is 21526221317. The reversal of 21526221304 is 40312262512.

It is a Harshad number since it is a multiple of its sum of digits (28).

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, 1820997 + ... + 1832779.

It is an arithmetic number, because the mean of its divisors is an integer number (405664200).

Almost surely, 2^21526221304 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21526221304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25962508800).

21526221304 is an abundant number, since it is smaller than the sum of its proper divisors (30398796296).

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

21526221304 is a wasteful number, since it uses less digits than its factorization.

21526221304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11933 (or 11929 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

Adding to 21526221304 its reverse (40312262512), we get a palindrome (61838483816).

The spelling of 21526221304 in words is "twenty-one billion, five hundred twenty-six million, two hundred twenty-one thousand, three hundred four".