21311023200 has 576 divisors, whose sum is σ = 79509911040. Its totient is φ = 4923555840.

The previous prime is 21311023177. The next prime is 21311023243. The reversal of 21311023200 is 232011312.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21311023200.

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, 28682029 + ... + 28682771.

It is an arithmetic number, because the mean of its divisors is an integer number (138038040).

Almost surely, 2^21311023200 is an apocalyptic number.

21311023200 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 21311023200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39754955520).

21311023200 is an abundant number, since it is smaller than the sum of its proper divisors (58198887840).

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

21311023200 is a wasteful number, since it uses less digits than its factorization.

21311023200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 839 (or 826 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21311023200 its reverse (232011312), we get a palindrome (21543034512).

The spelling of 21311023200 in words is "twenty-one billion, three hundred eleven million, twenty-three thousand, two hundred".