191661961349 has 2 divisors, whose sum is σ = 191661961350. Its totient is φ = 191661961348.

The previous prime is 191661961343. The next prime is 191661961409. The reversal of 191661961349 is 943169166191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136463748100 + 55198213249 = 369410^2 + 234943^2 .

It is a cyclic number.

It is not a de Polignac number, because 191661961349 - 2²⁸ = 191393525893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 191661961294 and 191661961303.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191661961343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95830980674 + 95830980675.

It is an arithmetic number, because the mean of its divisors is an integer number (95830980675).

Almost surely, 2^191661961349 is an apocalyptic number.

It is an amenable number.

191661961349 is a deficient number, since it is larger than the sum of its proper divisors (1).

191661961349 is an equidigital number, since it uses as much as digits as its factorization.

191661961349 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1889568, while the sum is 56.

The spelling of 191661961349 in words is "one hundred ninety-one billion, six hundred sixty-one million, nine hundred sixty-one thousand, three hundred forty-nine".