261674194681 has 3 divisors (see below), whose sum is σ = 261674706223. Its totient is φ = 261673683140.

The previous prime is 261674194633. The next prime is 261674194709. The reversal of 261674194681 is 186491476162.

The square root of 261674194681 is 511541.

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., 982258281 + 260691936400 = 31341^2 + 510580^2 .

It is not a de Polignac number, because 261674194681 - 2⁷ = 261674194553 is a prime.

It is a super-2 number, since 2×261674194681² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261674194081) 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, 255771 + ... + 767311.

Almost surely, 2^261674194681 is an apocalyptic number.

261674194681 is the 511541-st square number.

261674194681 is the 255771-st centered octagonal number.

It is an amenable number.

261674194681 is a deficient number, since it is larger than the sum of its proper divisors (511542).

261674194681 is an frugal number, since it uses more digits than its factorization.

261674194681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1023082 (or 511541 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 55.

The spelling of 261674194681 in words is "two hundred sixty-one billion, six hundred seventy-four million, one hundred ninety-four thousand, six hundred eighty-one".