1221100023120 has 80 divisors (see below), whose sum is σ = 3810479125632. Its totient is φ = 323470195200.

The previous prime is 1221100023109. The next prime is 1221100023127. The reversal of 1221100023120 is 213200011221.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1221100023120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221100023127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16811167 + ... + 16883646.

Almost surely, 2^{1221100023120} is an apocalyptic number.

1221100023120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221100023120 is an abundant number, since it is smaller than the sum of its proper divisors (2589379102512).

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

1221100023120 is a wasteful number, since it uses less digits than its factorization.

1221100023120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33694980 (or 33694974 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 1221100023120 its reverse (213200011221), we get a palindrome (1434300034341).

The spelling of 1221100023120 in words is "one trillion, two hundred twenty-one billion, one hundred million, twenty-three thousand, one hundred twenty".