21000233280 has 672 divisors, whose sum is σ = 79322810112. Its totient is φ = 4662558720.

The previous prime is 21000233273. The next prime is 21000233291. The reversal of 21000233280 is 8233200012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 203885709 + ... + 203885811.

It is an arithmetic number, because the mean of its divisors is an integer number (118039896).

Almost surely, 2^21000233280 is an apocalyptic number.

21000233280 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 21000233280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39661405056).

21000233280 is an abundant number, since it is smaller than the sum of its proper divisors (58322576832).

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

21000233280 is a wasteful number, since it uses less digits than its factorization.

21000233280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 174 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

Adding to 21000233280 its reverse (8233200012), we get a palindrome (29233433292).

The spelling of 21000233280 in words is "twenty-one billion, two hundred thirty-three thousand, two hundred eighty".