191648991 has 8 divisors (see below), whose sum is σ = 268981120. Its totient is φ = 121041432.

The previous prime is 191648983. The next prime is 191648993. The reversal of 191648991 is 199846191.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 191648991 - 2³ = 191648983 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 191648991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191648993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1681075 + ... + 1681188.

It is an arithmetic number, because the mean of its divisors is an integer number (33622640).

Almost surely, 2^191648991 is an apocalyptic number.

191648991 is a deficient number, since it is larger than the sum of its proper divisors (77332129).

191648991 is a wasteful number, since it uses less digits than its factorization.

191648991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3362285.

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

The square root of 191648991 is about 13843.7347200819. The cubic root of 191648991 is about 576.5480563225.

The spelling of 191648991 in words is "one hundred ninety-one million, six hundred forty-eight thousand, nine hundred ninety-one".