1991012200231 has 2 divisors, whose sum is σ = 1991012200232. Its totient is φ = 1991012200230.

The previous prime is 1991012200211. The next prime is 1991012200253. The reversal of 1991012200231 is 1320022101991.

It is a weak prime.

It is an emirp because it is prime and its reverse (1320022101991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1991012200231 - 2²⁹ = 1990475329319 is a prime.

It is a super-2 number, since 2×1991012200231² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1991012200193 and 1991012200202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1991012200211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995506100115 + 995506100116.

It is an arithmetic number, because the mean of its divisors is an integer number (995506100116).

Almost surely, 2^{1991012200231} is an apocalyptic number.

1991012200231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991012200231 is an equidigital number, since it uses as much as digits as its factorization.

1991012200231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 31.

The spelling of 1991012200231 in words is "one trillion, nine hundred ninety-one billion, twelve million, two hundred thousand, two hundred thirty-one".