258661 has 8 divisors (see below), whose sum is σ = 282744. Its totient is φ = 235200.

The previous prime is 258659. The next prime is 258673. The reversal of 258661 is 166852.

It can be written as a sum of positive squares in 4 ways, for example, as 136161 + 122500 = 369^2 + 350^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 258661 - 2¹ = 258659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (258611) by changing a digit.

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, 1215 + ... + 1411.

It is an arithmetic number, because the mean of its divisors is an integer number (35343).

2²⁵⁸⁶⁶¹ is an apocalyptic number.

It is an amenable number.

258661 is a deficient number, since it is larger than the sum of its proper divisors (24083).

258661 is a wasteful number, since it uses less digits than its factorization.

258661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311.

The product of its digits is 2880, while the sum is 28.

The square root of 258661 is about 508.5872589832. The cubic root of 258661 is about 63.7152880359.

Subtracting from 258661 its reverse (166852), we obtain a square (91809 = 303²).

It can be divided in two parts, 258 and 661, that added together give a palindrome (919).

The spelling of 258661 in words is "two hundred fifty-eight thousand, six hundred sixty-one".