21101212220 has 24 divisors (see below), whose sum is σ = 48340959408. Its totient is φ = 7673168000.

The previous prime is 21101212217. The next prime is 21101212229. The reversal of 21101212220 is 2221210112.

It is a super-2 number, since 2×21101212220² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21101212195 and 21101212204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101212229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47957081 + ... + 47957520.

It is an arithmetic number, because the mean of its divisors is an integer number (2014206642).

Almost surely, 2^21101212220 is an apocalyptic number.

21101212220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101212220 is an abundant number, since it is smaller than the sum of its proper divisors (27239747188).

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

21101212220 is a wasteful number, since it uses less digits than its factorization.

21101212220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95914621 (or 95914619 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21101212220 its reverse (2221210112), we get a palindrome (23322422332).

The spelling of 21101212220 in words is "twenty-one billion, one hundred one million, two hundred twelve thousand, two hundred twenty".