191486991 has 16 divisors (see below), whose sum is σ = 262046720. Its totient is φ = 124333920.

The previous prime is 191486989. The next prime is 191486993. The reversal of 191486991 is 199684191.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (191486989) and next prime (191486993).

It is not a de Polignac number, because 191486991 - 2¹ = 191486989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 191486991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191486993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13770 + ... + 23928.

It is an arithmetic number, because the mean of its divisors is an integer number (16377920).

Almost surely, 2^191486991 is an apocalyptic number.

191486991 is a deficient number, since it is larger than the sum of its proper divisors (70559729).

191486991 is a wasteful number, since it uses less digits than its factorization.

191486991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10326.

The product of its digits is 139968, while the sum is 48.

The square root of 191486991 is about 13837.8824608392. The cubic root of 191486991 is about 576.3855593985.

The spelling of 191486991 in words is "one hundred ninety-one million, four hundred eighty-six thousand, nine hundred ninety-one".