105891991 has 2 divisors, whose sum is σ = 105891992. Its totient is φ = 105891990.

The previous prime is 105891949. The next prime is 105892013. The reversal of 105891991 is 199198501.

It is a strong prime.

It is an emirp because it is prime and its reverse (199198501) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 105891991 - 2²¹ = 103794839 is a prime.

It is a super-2 number, since 2×105891991² = 22426227515888162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (105891901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52945995 + 52945996.

It is an arithmetic number, because the mean of its divisors is an integer number (52945996).

Almost surely, 2^105891991 is an apocalyptic number.

105891991 is a deficient number, since it is larger than the sum of its proper divisors (1).

105891991 is an equidigital number, since it uses as much as digits as its factorization.

105891991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29160, while the sum is 43.

The square root of 105891991 is about 10290.3834233716. The cubic root of 105891991 is about 473.1015504852.

The spelling of 105891991 in words is "one hundred five million, eight hundred ninety-one thousand, nine hundred ninety-one".