191004391 has 2 divisors, whose sum is σ = 191004392. Its totient is φ = 191004390.

The previous prime is 191004377. The next prime is 191004431. The reversal of 191004391 is 193400191.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 191004391 - 2¹³ = 190996199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191004301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95502195 + 95502196.

It is an arithmetic number, because the mean of its divisors is an integer number (95502196).

Almost surely, 2^191004391 is an apocalyptic number.

191004391 is a deficient number, since it is larger than the sum of its proper divisors (1).

191004391 is an equidigital number, since it uses as much as digits as its factorization.

191004391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 191004391 is about 13820.4338209768. The cubic root of 191004391 is about 575.9009352120.

The spelling of 191004391 in words is "one hundred ninety-one million, four thousand, three hundred ninety-one".