21123330320 has 80 divisors (see below), whose sum is σ = 51323500800. Its totient is φ = 8077181952.

The previous prime is 21123330317. The next prime is 21123330337. The reversal of 21123330320 is 2303332112.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21123330292 and 21123330301.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96356 + ... + 227004.

It is an arithmetic number, because the mean of its divisors is an integer number (641543760).

Almost surely, 2^21123330320 is an apocalyptic number.

21123330320 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 21123330320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25661750400).

21123330320 is an abundant number, since it is smaller than the sum of its proper divisors (30200170480).

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

21123330320 is a wasteful number, since it uses less digits than its factorization.

21123330320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130752 (or 130746 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 20.

Adding to 21123330320 its reverse (2303332112), we get a palindrome (23426662432).

The spelling of 21123330320 in words is "twenty-one billion, one hundred twenty-three million, three hundred thirty thousand, three hundred twenty".