191091983 has 4 divisors (see below), whose sum is σ = 191226768. Its totient is φ = 190957200.

The previous prime is 191091941. The next prime is 191091997. The reversal of 191091983 is 389190191.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 191091983 - 2⁶ = 191091919 is a prime.

It is a super-2 number, since 2×191091983² = 73032291933744578, which contains 22 as substring.

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 191091983.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191091913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65243 + ... + 68108.

It is an arithmetic number, because the mean of its divisors is an integer number (47806692).

Almost surely, 2^191091983 is an apocalyptic number.

191091983 is a deficient number, since it is larger than the sum of its proper divisors (134785).

191091983 is a wasteful number, since it uses less digits than its factorization.

191091983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134784.

The product of its (nonzero) digits is 17496, while the sum is 41.

The square root of 191091983 is about 13823.6023886684. The cubic root of 191091983 is about 575.9889551878.

The spelling of 191091983 in words is "one hundred ninety-one million, ninety-one thousand, nine hundred eighty-three".