21001300320 has 768 divisors, whose sum is σ = 89860700160. Its totient is φ = 3981312000.

The previous prime is 21001300289. The next prime is 21001300351. The reversal of 21001300320 is 2300310012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21001300289) and next prime (21001300351).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21001300296 and 21001300305.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 52372120 + ... + 52372520.

It is an arithmetic number, because the mean of its divisors is an integer number (117006120).

Almost surely, 2^21001300320 is an apocalyptic number.

21001300320 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 21001300320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44930350080).

21001300320 is an abundant number, since it is smaller than the sum of its proper divisors (68859399840).

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

21001300320 is a wasteful number, since it uses less digits than its factorization.

21001300320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559 (or 551 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

Adding to 21001300320 its reverse (2300310012), we get a palindrome (23301610332).

The spelling of 21001300320 in words is "twenty-one billion, one million, three hundred thousand, three hundred twenty".