261508 has 24 divisors (see below), whose sum is σ = 508032. Its totient is φ = 117024.

The previous prime is 261467. The next prime is 261509. The reversal of 261508 is 805162.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (261509) by changing a digit.

261508 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2391 + ... + 2497.

It is an arithmetic number, because the mean of its divisors is an integer number (21168).

2²⁶¹⁵⁰⁸ is an apocalyptic number.

It is an amenable number.

261508 is a deficient number, since it is larger than the sum of its proper divisors (246524).

261508 is a wasteful number, since it uses less digits than its factorization.

261508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171 (or 169 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 261508 is about 511.3785290761. The cubic root of 261508 is about 63.9482002736.

The spelling of 261508 in words is "two hundred sixty-one thousand, five hundred eight".