195961391 has 2 divisors, whose sum is σ = 195961392. Its totient is φ = 195961390.

The previous prime is 195961387. The next prime is 195961393. The reversal of 195961391 is 193169591.

It is a strong prime.

It is an emirp because it is prime and its reverse (193169591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 195961391 - 2² = 195961387 is a prime.

Together with 195961393, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195961393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97980695 + 97980696.

It is an arithmetic number, because the mean of its divisors is an integer number (97980696).

Almost surely, 2^195961391 is an apocalyptic number.

195961391 is a deficient number, since it is larger than the sum of its proper divisors (1).

195961391 is an equidigital number, since it uses as much as digits as its factorization.

195961391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 65610, while the sum is 44.

The square root of 195961391 is about 13998.6210392310. The cubic root of 195961391 is about 580.8404294557.

It can be divided in two parts, 19596 and 1391, that multiplied together give a triangular number (27258036 = T₇₃₈₃).

The spelling of 195961391 in words is "one hundred ninety-five million, nine hundred sixty-one thousand, three hundred ninety-one".