21231172200 has 192 divisors, whose sum is σ = 75286609920. Its totient is φ = 4848480000.

The previous prime is 21231172169. The next prime is 21231172201. The reversal of 21231172200 is 227113212.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21231172201) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8192905 + ... + 8195495.

It is an arithmetic number, because the mean of its divisors is an integer number (392117760).

Almost surely, 2^21231172200 is an apocalyptic number.

21231172200 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 21231172200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37643304960).

21231172200 is an abundant number, since it is smaller than the sum of its proper divisors (54055437720).

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

21231172200 is a wasteful number, since it uses less digits than its factorization.

21231172200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4568 (or 4559 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 21.

Adding to 21231172200 its reverse (227113212), we get a palindrome (21458285412).

The spelling of 21231172200 in words is "twenty-one billion, two hundred thirty-one million, one hundred seventy-two thousand, two hundred".