261604459 has 2 divisors, whose sum is σ = 261604460. Its totient is φ = 261604458.

The previous prime is 261604433. The next prime is 261604481. The reversal of 261604459 is 954406162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261604459 - 2¹⁵ = 261571691 is a prime.

It is not a weakly prime, because it can be changed into another prime (261607459) 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, 130802229 + 130802230.

It is an arithmetic number, because the mean of its divisors is an integer number (130802230).

Almost surely, 2^261604459 is an apocalyptic number.

261604459 is a deficient number, since it is larger than the sum of its proper divisors (1).

261604459 is an equidigital number, since it uses as much as digits as its factorization.

261604459 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 261604459 is about 16174.1911389720. The cubic root of 261604459 is about 639.5606188295.

The spelling of 261604459 in words is "two hundred sixty-one million, six hundred four thousand, four hundred fifty-nine".