21100012220 has 24 divisors (see below), whose sum is σ = 50640029664. Its totient is φ = 7234289856.

The previous prime is 21100012189. The next prime is 21100012249. The reversal of 21100012220 is 2221000112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75357047 + ... + 75357326.

It is an arithmetic number, because the mean of its divisors is an integer number (2110001236).

Almost surely, 2^21100012220 is an apocalyptic number.

21100012220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100012220 is an abundant number, since it is smaller than the sum of its proper divisors (29540017444).

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

21100012220 is a wasteful number, since it uses less digits than its factorization.

21100012220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150714389 (or 150714387 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21100012220 its reverse (2221000112), we get a palindrome (23321012332).

The spelling of 21100012220 in words is "twenty-one billion, one hundred million, twelve thousand, two hundred twenty".