1221200120000 has 140 divisors (see below), whose sum is σ = 3460777259280. Its totient is φ = 418697088000.

The previous prime is 1221200119999. The next prime is 1221200120003. The reversal of 1221200120000 is 210021221.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (140).

It is not an unprimeable number, because it can be changed into a prime (1221200120003) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1900715 + ... + 2460714.

Almost surely, 2^{1221200120000} is an apocalyptic number.

1221200120000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221200120000 is an abundant number, since it is smaller than the sum of its proper divisors (2239577139280).

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

1221200120000 is an frugal number, since it uses more digits than its factorization.

1221200120000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4361468 (or 4361443 counting only the distinct ones).

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

Adding to 1221200120000 its reverse (210021221), we get a palindrome (1221410141221).

The spelling of 1221200120000 in words is "one trillion, two hundred twenty-one billion, two hundred million, one hundred twenty thousand".