261673251869 has 2 divisors, whose sum is σ = 261673251870. Its totient is φ = 261673251868.

The previous prime is 261673251821. The next prime is 261673251899. The reversal of 261673251869 is 968152376162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 231332140900 + 30341110969 = 480970^2 + 174187^2 .

It is a cyclic number.

It is not a de Polignac number, because 261673251869 - 2²⁰ = 261672203293 is a prime.

It is a super-2 number, since 2×261673251869² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261673251899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130836625934 + 130836625935.

It is an arithmetic number, because the mean of its divisors is an integer number (130836625935).

Almost surely, 2^261673251869 is an apocalyptic number.

It is an amenable number.

261673251869 is a deficient number, since it is larger than the sum of its proper divisors (1).

261673251869 is an equidigital number, since it uses as much as digits as its factorization.

261673251869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6531840, while the sum is 56.

The spelling of 261673251869 in words is "two hundred sixty-one billion, six hundred seventy-three million, two hundred fifty-one thousand, eight hundred sixty-nine".