21012100220 has 48 divisors (see below), whose sum is σ = 45664063200. Its totient is φ = 8111980800.

The previous prime is 21012100211. The next prime is 21012100231. The reversal of 21012100220 is 2200121012.

It is a happy number.

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, 2117270 + ... + 2127170.

It is an arithmetic number, because the mean of its divisors is an integer number (951334650).

Almost surely, 2^21012100220 is an apocalyptic number.

21012100220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012100220 is an abundant number, since it is smaller than the sum of its proper divisors (24651962980).

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

21012100220 is a wasteful number, since it uses less digits than its factorization.

21012100220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13598 (or 13596 counting only the distinct ones).

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

Adding to 21012100220 its reverse (2200121012), we get a palindrome (23212221232).

The spelling of 21012100220 in words is "twenty-one billion, twelve million, one hundred thousand, two hundred twenty".