261683720951 has 2 divisors, whose sum is σ = 261683720952. Its totient is φ = 261683720950.

The previous prime is 261683720929. The next prime is 261683720953. The reversal of 261683720951 is 159027386162.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261683720951 - 2⁶ = 261683720887 is a prime.

Together with 261683720953, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261683720951.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261683720953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130841860475 + 130841860476.

It is an arithmetic number, because the mean of its divisors is an integer number (130841860476).

Almost surely, 2^261683720951 is an apocalyptic number.

261683720951 is a deficient number, since it is larger than the sum of its proper divisors (1).

261683720951 is an equidigital number, since it uses as much as digits as its factorization.

261683720951 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1088640, while the sum is 50.

The spelling of 261683720951 in words is "two hundred sixty-one billion, six hundred eighty-three million, seven hundred twenty thousand, nine hundred fifty-one".