21205500288 has 256 divisors, whose sum is σ = 66242880000. Its totient is φ = 6007572480.

The previous prime is 21205500271. The next prime is 21205500289. The reversal of 21205500288 is 88200550212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21205500289) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17253658 + ... + 17254886.

It is an arithmetic number, because the mean of its divisors is an integer number (258761250).

Almost surely, 2^21205500288 is an apocalyptic number.

21205500288 is a gapful number since it is divisible by the number (28) 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 21205500288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33121440000).

21205500288 is an abundant number, since it is smaller than the sum of its proper divisors (45037379712).

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

21205500288 is a wasteful number, since it uses less digits than its factorization.

21205500288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1398 (or 1372 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 33.

The spelling of 21205500288 in words is "twenty-one billion, two hundred five million, five hundred thousand, two hundred eighty-eight".