261604523 has 4 divisors (see below), whose sum is σ = 261654888. Its totient is φ = 261554160.

The previous prime is 261604513. The next prime is 261604529. The reversal of 261604523 is 325406162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261604523 - 2⁶ = 261604459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261604529) 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 in 3 ways as a sum of consecutive naturals, for example, 16361 + ... + 28122.

It is an arithmetic number, because the mean of its divisors is an integer number (65413722).

Almost surely, 2^261604523 is an apocalyptic number.

261604523 is a deficient number, since it is larger than the sum of its proper divisors (50365).

261604523 is an equidigital number, since it uses as much as digits as its factorization.

261604523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50364.

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

The square root of 261604523 is about 16174.1931174325. The cubic root of 261604523 is about 639.5606709844.

The spelling of 261604523 in words is "two hundred sixty-one million, six hundred four thousand, five hundred twenty-three".