1221211121200 has 120 divisors (see below), whose sum is σ = 3379500142592. Its totient is φ = 415403976960.

The previous prime is 1221211121177. The next prime is 1221211121269. The reversal of 1221211121200 is 21211121221.

It is a super-2 number, since 2×1221211121200² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1361514 + ... + 2072713.

Almost surely, 2^{1221211121200} is an apocalyptic number.

1221211121200 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221211121200 is an abundant number, since it is smaller than the sum of its proper divisors (2158289021392).

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

1221211121200 is a wasteful number, since it uses less digits than its factorization.

1221211121200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3434379 (or 3434368 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221211121200 its reverse (21211121221), we get a palindrome (1242422242421).

The spelling of 1221211121200 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, one hundred twenty-one thousand, two hundred".