194517163681 has 3 divisors (see below), whose sum is σ = 194517604723. Its totient is φ = 194516722640.

The previous prime is 194517163637. The next prime is 194517163693. The reversal of 194517163681 is 186361715491.

It is a happy number.

The square root of 194517163681 is 441041.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 318301281 + 194198862400 = 17841^2 + 440680^2 .

It is not a de Polignac number, because 194517163681 - 2¹⁷ = 194517032609 is a prime.

It is a super-2 number, since 2×194517163681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (194517163081) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 220521 + ... + 661561.

Almost surely, 2^194517163681 is an apocalyptic number.

194517163681 is the 441041-st square number.

194517163681 is the 220521-st centered octagonal number.

It is an amenable number.

194517163681 is a deficient number, since it is larger than the sum of its proper divisors (441042).

194517163681 is an frugal number, since it uses more digits than its factorization.

194517163681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 882082 (or 441041 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 52.

The spelling of 194517163681 in words is "one hundred ninety-four billion, five hundred seventeen million, one hundred sixty-three thousand, six hundred eighty-one".