191388507643831 has 2 divisors, whose sum is σ = 191388507643832. Its totient is φ = 191388507643830.

The previous prime is 191388507643807. The next prime is 191388507643981. The reversal of 191388507643831 is 138346705883191.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 191388507643831 - 2¹³ = 191388507635639 is a prime.

It is a super-2 number, since 2×191388507643831² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191388507640831) 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, 95694253821915 + 95694253821916.

It is an arithmetic number, because the mean of its divisors is an integer number (95694253821916).

Almost surely, 2^{191388507643831} is an apocalyptic number.

191388507643831 is a deficient number, since it is larger than the sum of its proper divisors (1).

191388507643831 is an equidigital number, since it uses as much as digits as its factorization.

191388507643831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 104509440, while the sum is 67.

The spelling of 191388507643831 in words is "one hundred ninety-one trillion, three hundred eighty-eight billion, five hundred seven million, six hundred forty-three thousand, eight hundred thirty-one".