1221210100220 has 96 divisors (see below), whose sum is σ = 2826040928256. Its totient is φ = 439578547200.

The previous prime is 1221210100147. The next prime is 1221210100261. The reversal of 1221210100220 is 220010121221.

It is a junction number, because it is equal to n+sod(n) for n = 1221210100195 and 1221210100204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60514772 + ... + 60534948.

It is an arithmetic number, because the mean of its divisors is an integer number (29437926336).

Almost surely, 2^{1221210100220} is an apocalyptic number.

1221210100220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221210100220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1413020464128).

1221210100220 is an abundant number, since it is smaller than the sum of its proper divisors (1604830828036).

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

1221210100220 is a wasteful number, since it uses less digits than its factorization.

1221210100220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22971 (or 22969 counting only the distinct ones).

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

Adding to 1221210100220 its reverse (220010121221), we get a palindrome (1441220221441).

The spelling of 1221210100220 in words is "one trillion, two hundred twenty-one billion, two hundred ten million, one hundred thousand, two hundred twenty".