21021100320 has 192 divisors, whose sum is σ = 72310081536. Its totient is φ = 5090810880.

The previous prime is 21021100313. The next prime is 21021100333. The reversal of 21021100320 is 2300112012.

21021100320 = T₁₂₁ + T₁₂₂ + ... + T₅₀₁₄.

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 = 21021100296 and 21021100305.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8589337 + ... + 8591783.

It is an arithmetic number, because the mean of its divisors is an integer number (376615008).

Almost surely, 2^21021100320 is an apocalyptic number.

21021100320 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 21021100320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36155040768).

21021100320 is an abundant number, since it is smaller than the sum of its proper divisors (51288981216).

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

21021100320 is a wasteful number, since it uses less digits than its factorization.

21021100320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4103 (or 4095 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21021100320 its reverse (2300112012), we get a palindrome (23321212332).

The spelling of 21021100320 in words is "twenty-one billion, twenty-one million, one hundred thousand, three hundred twenty".