261315559 has 2 divisors, whose sum is σ = 261315560. Its totient is φ = 261315558.

The previous prime is 261315553. The next prime is 261315679. The reversal of 261315559 is 955513162.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261315559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261315553) 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, 130657779 + 130657780.

It is an arithmetic number, because the mean of its divisors is an integer number (130657780).

Almost surely, 2^261315559 is an apocalyptic number.

261315559 is a deficient number, since it is larger than the sum of its proper divisors (1).

261315559 is an equidigital number, since it uses as much as digits as its factorization.

261315559 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40500, while the sum is 37.

The square root of 261315559 is about 16165.2577770972. The cubic root of 261315559 is about 639.3251015386.

The spelling of 261315559 in words is "two hundred sixty-one million, three hundred fifteen thousand, five hundred fifty-nine".