1221012100120 has 32 divisors (see below), whose sum is σ = 2778145516800. Its totient is φ = 482917143808.

The previous prime is 1221012100093. The next prime is 1221012100123. The reversal of 1221012100120 is 210012101221.

It is a self number, because there is not a number n which added to its sum of digits gives 1221012100120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221012100123) 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, 171486904 + ... + 171494023.

It is an arithmetic number, because the mean of its divisors is an integer number (86817047400).

Almost surely, 2^{1221012100120} is an apocalyptic number.

1221012100120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221012100120 is an abundant number, since it is smaller than the sum of its proper divisors (1557133416680).

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

1221012100120 is a wasteful number, since it uses less digits than its factorization.

1221012100120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342981027 (or 342981023 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1221012100120 its reverse (210012101221), we get a palindrome (1431024201341).

The spelling of 1221012100120 in words is "one trillion, two hundred twenty-one billion, twelve million, one hundred thousand, one hundred twenty".