1200002121991 has 2 divisors, whose sum is σ = 1200002121992. Its totient is φ = 1200002121990.

The previous prime is 1200002121977. The next prime is 1200002122043. The reversal of 1200002121991 is 1991212000021.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1200002121991 - 2¹⁹ = 1200001597703 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1200002121931) by changing a digit.

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 as a sum of consecutive naturals, namely, 600001060995 + 600001060996.

It is an arithmetic number, because the mean of its divisors is an integer number (600001060996).

Almost surely, 2^{1200002121991} is an apocalyptic number.

1200002121991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1200002121991 is an equidigital number, since it uses as much as digits as its factorization.

1200002121991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 28.

The spelling of 1200002121991 in words is "one trillion, two hundred billion, two million, one hundred twenty-one thousand, nine hundred ninety-one".