21012111320 has 64 divisors (see below), whose sum is σ = 49251434400. Its totient is φ = 8060830720.

The previous prime is 21012111319. The next prime is 21012111377. The reversal of 21012111320 is 2311121012.

It is a junction number, because it is equal to n+sod(n) for n = 21012111295 and 21012111304.

It is a congruent number.

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, 11819 + ... + 205338.

Almost surely, 2^21012111320 is an apocalyptic number.

21012111320 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 21012111320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24625717200).

21012111320 is an abundant number, since it is smaller than the sum of its proper divisors (28239323080).

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

21012111320 is a wasteful number, since it uses less digits than its factorization.

21012111320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217268 (or 217264 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21012111320 its reverse (2311121012), we get a palindrome (23323232332).

The spelling of 21012111320 in words is "twenty-one billion, twelve million, one hundred eleven thousand, three hundred twenty".