1200201991 has 2 divisors, whose sum is σ = 1200201992. Its totient is φ = 1200201990.

The previous prime is 1200201973. The next prime is 1200202001. The reversal of 1200201991 is 1991020021.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1200201991 - 2²¹ = 1198104839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1200201391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 600100995 + 600100996.

It is an arithmetic number, because the mean of its divisors is an integer number (600100996).

Almost surely, 2^1200201991 is an apocalyptic number.

1200201991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1200201991 is an equidigital number, since it uses as much as digits as its factorization.

1200201991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 1200201991 is about 34643.9315176554. The cubic root of 1200201991 is about 1062.7181901339.

The spelling of 1200201991 in words is "one billion, two hundred million, two hundred one thousand, nine hundred ninety-one".