21520890000 has 375 divisors, whose sum is σ = 78315152223. Its totient is φ = 5703696000.

The previous prime is 21520889969. The next prime is 21520890023. The reversal of 21520890000 is 9802512.

The square root of 21520890000 is 146700.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 1687237776 + 19833652224 = 41076^2 + 140832^2 .

It is a tau number, because it is divible by the number of its divisors (375).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 74 ways as a sum of consecutive naturals, for example, 132029919 + ... + 132030081.

Almost surely, 2^21520890000 is an apocalyptic number.

21520890000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21520890000 is the 146700-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21520890000

21520890000 is an abundant number, since it is smaller than the sum of its proper divisors (56794262223).

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

21520890000 is an frugal number, since it uses more digits than its factorization.

21520890000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The spelling of 21520890000 in words is "twenty-one billion, five hundred twenty million, eight hundred ninety thousand".