200121111991 has 2 divisors, whose sum is σ = 200121111992. Its totient is φ = 200121111990.

The previous prime is 200121111947. The next prime is 200121112003. The reversal of 200121111991 is 199111121002.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 200121111991 - 2²³ = 200112723383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (200121111901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100060555995 + 100060555996.

It is an arithmetic number, because the mean of its divisors is an integer number (100060555996).

Almost surely, 2^200121111991 is an apocalyptic number.

200121111991 is a deficient number, since it is larger than the sum of its proper divisors (1).

200121111991 is an equidigital number, since it uses as much as digits as its factorization.

200121111991 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 28.

Adding to 200121111991 its reverse (199111121002), we get a palindrome (399232232993).

The spelling of 200121111991 in words is "two hundred billion, one hundred twenty-one million, one hundred eleven thousand, nine hundred ninety-one".