21100012320 has 192 divisors, whose sum is σ = 70665364224. Its totient is φ = 5280337920.

The previous prime is 21100012279. The next prime is 21100012333. The reversal of 21100012320 is 2321000112.

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 = 21100012296 and 21100012305.

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, 567090 + ... + 603150.

It is an arithmetic number, because the mean of its divisors is an integer number (368048772).

Almost surely, 2^21100012320 is an apocalyptic number.

21100012320 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 21100012320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35332682112).

21100012320 is an abundant number, since it is smaller than the sum of its proper divisors (49565351904).

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

21100012320 is a wasteful number, since it uses less digits than its factorization.

21100012320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36155 (or 36147 counting only the distinct ones).

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

Adding to 21100012320 its reverse (2321000112), we get a palindrome (23421012432).

The spelling of 21100012320 in words is "twenty-one billion, one hundred million, twelve thousand, three hundred twenty".