21011112220 has 48 divisors (see below), whose sum is σ = 50450984640. Its totient is φ = 7200336384.

The previous prime is 21011112217. The next prime is 21011112223. The reversal of 21011112220 is 2221111012.

It is an interprime number because it is at equal distance from previous prime (21011112217) and next prime (21011112223).

It is a self number, because there is not a number n which added to its sum of digits gives 21011112220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011112223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 264066 + ... + 334294.

It is an arithmetic number, because the mean of its divisors is an integer number (1051062180).

Almost surely, 2^21011112220 is an apocalyptic number.

21011112220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21011112220 is an abundant number, since it is smaller than the sum of its proper divisors (29439872420).

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

21011112220 is a wasteful number, since it uses less digits than its factorization.

21011112220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72382 (or 72380 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21011112220 its reverse (2221111012), we get a palindrome (23232223232).

The spelling of 21011112220 in words is "twenty-one billion, eleven million, one hundred twelve thousand, two hundred twenty".