1221002120999 has 4 divisors (see below), whose sum is σ = 1221005376864. Its totient is φ = 1220998865136.

The previous prime is 1221002120981. The next prime is 1221002121041. The reversal of 1221002120999 is 9990212001221.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221002120999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221002120599) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 979247 + ... + 1844160.

It is an arithmetic number, because the mean of its divisors is an integer number (305251344216).

Almost surely, 2^{1221002120999} is an apocalyptic number.

1221002120999 is a deficient number, since it is larger than the sum of its proper divisors (3255865).

1221002120999 is an equidigital number, since it uses as much as digits as its factorization.

1221002120999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3255864.

The product of its (nonzero) digits is 11664, while the sum is 38.

The spelling of 1221002120999 in words is "one trillion, two hundred twenty-one billion, two million, one hundred twenty thousand, nine hundred ninety-nine".