261673251839 has 4 divisors (see below), whose sum is σ = 261758241360. Its totient is φ = 261588262320.

The previous prime is 261673251821. The next prime is 261673251869. The reversal of 261673251839 is 938152376162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261673251839 - 2²⁸ = 261404816383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261673251869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42490142 + ... + 42496299.

It is an arithmetic number, because the mean of its divisors is an integer number (65439560340).

Almost surely, 2^261673251839 is an apocalyptic number.

261673251839 is a deficient number, since it is larger than the sum of its proper divisors (84989521).

261673251839 is an equidigital number, since it uses as much as digits as its factorization.

261673251839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84989520.

The product of its digits is 3265920, while the sum is 53.

The spelling of 261673251839 in words is "two hundred sixty-one billion, six hundred seventy-three million, two hundred fifty-one thousand, eight hundred thirty-nine".