401243185991 has 2 divisors, whose sum is σ = 401243185992. Its totient is φ = 401243185990.

The previous prime is 401243185979. The next prime is 401243185997. The reversal of 401243185991 is 199581342104.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 401243185991 - 2³⁴ = 384063316807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (401243185997) 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, 200621592995 + 200621592996.

It is an arithmetic number, because the mean of its divisors is an integer number (200621592996).

Almost surely, 2^401243185991 is an apocalyptic number.

401243185991 is a deficient number, since it is larger than the sum of its proper divisors (1).

401243185991 is an equidigital number, since it uses as much as digits as its factorization.

401243185991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 47.

The spelling of 401243185991 in words is "four hundred one billion, two hundred forty-three million, one hundred eighty-five thousand, nine hundred ninety-one".