191397919 has 2 divisors, whose sum is σ = 191397920. Its totient is φ = 191397918.

The previous prime is 191397851. The next prime is 191397953. The reversal of 191397919 is 919793191.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 191397919 - 2²⁷ = 57180191 is a prime.

It is a super-2 number, since 2×191397919² = 73266326795061122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191397979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95698959 + 95698960.

It is an arithmetic number, because the mean of its divisors is an integer number (95698960).

Almost surely, 2^191397919 is an apocalyptic number.

191397919 is a deficient number, since it is larger than the sum of its proper divisors (1).

191397919 is an equidigital number, since it uses as much as digits as its factorization.

191397919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 137781, while the sum is 49.

The square root of 191397919 is about 13834.6636749868. The cubic root of 191397919 is about 576.2961751246.

The spelling of 191397919 in words is "one hundred ninety-one million, three hundred ninety-seven thousand, nine hundred nineteen".