20111232331991 has 2 divisors, whose sum is σ = 20111232331992. Its totient is φ = 20111232331990.

The previous prime is 20111232331987. The next prime is 20111232332017. The reversal of 20111232331991 is 19913323211102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20111232331991 - 2² = 20111232331987 is a prime.

It is a super-2 number, since 2×20111232331991² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20111232337991) 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, 10055616165995 + 10055616165996.

It is an arithmetic number, because the mean of its divisors is an integer number (10055616165996).

Almost surely, 2^{20111232331991} is an apocalyptic number.

20111232331991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20111232331991 is an equidigital number, since it uses as much as digits as its factorization.

20111232331991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 38.

The spelling of 20111232331991 in words is "twenty trillion, one hundred eleven billion, two hundred thirty-two million, three hundred thirty-one thousand, nine hundred ninety-one".