261664727 has 2 divisors, whose sum is σ = 261664728. Its totient is φ = 261664726.

The previous prime is 261664723. The next prime is 261664759. The reversal of 261664727 is 727466162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261664727 - 2² = 261664723 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261664723) 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, 130832363 + 130832364.

It is an arithmetic number, because the mean of its divisors is an integer number (130832364).

Almost surely, 2^261664727 is an apocalyptic number.

261664727 is a deficient number, since it is larger than the sum of its proper divisors (1).

261664727 is an equidigital number, since it uses as much as digits as its factorization.

261664727 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 41.

The square root of 261664727 is about 16176.0541233021. The cubic root of 261664727 is about 639.6097286955.

The spelling of 261664727 in words is "two hundred sixty-one million, six hundred sixty-four thousand, seven hundred twenty-seven".