191783381 has 2 divisors, whose sum is σ = 191783382. Its totient is φ = 191783380.

The previous prime is 191783303. The next prime is 191783387. The reversal of 191783381 is 183387191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 183169156 + 8614225 = 13534^2 + 2935^2 .

It is a cyclic number.

It is not a de Polignac number, because 191783381 - 2¹⁴ = 191766997 is a prime.

It is a super-2 number, since 2×191783381² = 73561730455582322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191783387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95891690 + 95891691.

It is an arithmetic number, because the mean of its divisors is an integer number (95891691).

Almost surely, 2^191783381 is an apocalyptic number.

It is an amenable number.

191783381 is a deficient number, since it is larger than the sum of its proper divisors (1).

191783381 is an equidigital number, since it uses as much as digits as its factorization.

191783381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 41.

The square root of 191783381 is about 13848.5876897249. The cubic root of 191783381 is about 576.6827890771.

The spelling of 191783381 in words is "one hundred ninety-one million, seven hundred eighty-three thousand, three hundred eighty-one".