1221021001200 has 1920 divisors, whose sum is σ = 5474993577984. Its totient is φ = 224446464000.

The previous prime is 1221021001183. The next prime is 1221021001217. The reversal of 1221021001200 is 21001201221.

It is an interprime number because it is at equal distance from previous prime (1221021001183) and next prime (1221021001217).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 3688885035 + ... + 3688885365.

Almost surely, 2^{1221021001200} is an apocalyptic number.

1221021001200 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 1221021001200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2737496788992).

1221021001200 is an abundant number, since it is smaller than the sum of its proper divisors (4253972576784).

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

1221021001200 is a wasteful number, since it uses less digits than its factorization.

1221021001200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503 (or 492 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 1221021001200 its reverse (21001201221), we get a palindrome (1242022202421).

The spelling of 1221021001200 in words is "one trillion, two hundred twenty-one billion, twenty-one million, one thousand, two hundred".