261677951 has 2 divisors, whose sum is σ = 261677952. Its totient is φ = 261677950.

The previous prime is 261677939. The next prime is 261677953. The reversal of 261677951 is 159776162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261677951 - 2⁶ = 261677887 is a prime.

Together with 261677953, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261677953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130838975 + 130838976.

It is an arithmetic number, because the mean of its divisors is an integer number (130838976).

Almost surely, 2^261677951 is an apocalyptic number.

261677951 is a deficient number, since it is larger than the sum of its proper divisors (1).

261677951 is an equidigital number, since it uses as much as digits as its factorization.

261677951 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 158760, while the sum is 44.

The square root of 261677951 is about 16176.4628704794. The cubic root of 261677951 is about 639.6205033697.

The spelling of 261677951 in words is "two hundred sixty-one million, six hundred seventy-seven thousand, nine hundred fifty-one".