261240563 has 2 divisors, whose sum is σ = 261240564. Its totient is φ = 261240562.

The previous prime is 261240541. The next prime is 261240569. The reversal of 261240563 is 365042162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261240563 - 2²² = 257046259 is a prime.

It is not a weakly prime, because it can be changed into another prime (261240569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130620281 + 130620282.

It is an arithmetic number, because the mean of its divisors is an integer number (130620282).

Almost surely, 2^261240563 is an apocalyptic number.

261240563 is a deficient number, since it is larger than the sum of its proper divisors (1).

261240563 is an equidigital number, since it uses as much as digits as its factorization.

261240563 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 261240563 is about 16162.9379445694. The cubic root of 261240563 is about 639.2639348620.

The spelling of 261240563 in words is "two hundred sixty-one million, two hundred forty thousand, five hundred sixty-three".