21221012100220 has 24 divisors (see below), whose sum is σ = 44564214240000. Its totient is φ = 8488387920192.

The previous prime is 21221012100217. The next prime is 21221012100317. The reversal of 21221012100220 is 2200121012212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21221012100194 and 21221012100203.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15716406 + ... + 17013154.

It is an arithmetic number, because the mean of its divisors is an integer number (1856842260000).

Almost surely, 2^{21221012100220} is an apocalyptic number.

21221012100220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221012100220 is an abundant number, since it is smaller than the sum of its proper divisors (23343202139780).

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

21221012100220 is a wasteful number, since it uses less digits than its factorization.

21221012100220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2114997 (or 2114995 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21221012100220 its reverse (2200121012212), we get a palindrome (23421133112432).

The spelling of 21221012100220 in words is "twenty-one trillion, two hundred twenty-one billion, twelve million, one hundred thousand, two hundred twenty".