21210230400 has 192 divisors, whose sum is σ = 70375495680. Its totient is φ = 5614428160.

The previous prime is 21210230399. The next prime is 21210230417. The reversal of 21210230400 is 403201212.

It is a tau number, because it is divible by the number of its divisors (192).

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 21210230400.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1307137 + ... + 1323263.

It is an arithmetic number, because the mean of its divisors is an integer number (366539040).

Almost surely, 2^21210230400 is an apocalyptic number.

21210230400 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 21210230400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35187747840).

21210230400 is an abundant number, since it is smaller than the sum of its proper divisors (49165265280).

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

21210230400 is a wasteful number, since it uses less digits than its factorization.

21210230400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16291 (or 16274 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 21210230400 its reverse (403201212), we get a palindrome (21613431612).

The spelling of 21210230400 in words is "twenty-one billion, two hundred ten million, two hundred thirty thousand, four hundred".