194163938509381 has 2 divisors, whose sum is σ = 194163938509382. Its totient is φ = 194163938509380.

The previous prime is 194163938509367. The next prime is 194163938509469. The reversal of 194163938509381 is 183905839361491.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 193472103830625 + 691834678756 = 13909425^2 + 831766^2 .

It is a cyclic number.

It is not a de Polignac number, because 194163938509381 - 2¹¹ = 194163938507333 is a prime.

It is a super-2 number, since 2×194163938509381² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 194163938509381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194163938509351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97081969254690 + 97081969254691.

It is an arithmetic number, because the mean of its divisors is an integer number (97081969254691).

Almost surely, 2^{194163938509381} is an apocalyptic number.

It is an amenable number.

194163938509381 is a deficient number, since it is larger than the sum of its proper divisors (1).

194163938509381 is an equidigital number, since it uses as much as digits as its factorization.

194163938509381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 151165440, while the sum is 70.

The spelling of 194163938509381 in words is "one hundred ninety-four trillion, one hundred sixty-three billion, nine hundred thirty-eight million, five hundred nine thousand, three hundred eighty-one".