261723 has 24 divisors (see below), whose sum is σ = 442624. Its totient is φ = 134640.

The previous prime is 261721. The next prime is 261739. The reversal of 261723 is 327162.

It is a happy number.

It is not a de Polignac number, because 261723 - 2¹ = 261721 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 261723.

It is not an unprimeable number, because it can be changed into a prime (261721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2490 + ... + 2592.

2²⁶¹⁷²³ is an apocalyptic number.

261723 is a deficient number, since it is larger than the sum of its proper divisors (180901).

261723 is a wasteful number, since it uses less digits than its factorization.

261723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 124 counting only the distinct ones).

The product of its digits is 504, while the sum is 21.

The square root of 261723 is about 511.5887019863. The cubic root of 261723 is about 63.9657205750.

Adding to 261723 its reverse (327162), we get a palindrome (588885).

The spelling of 261723 in words is "two hundred sixty-one thousand, seven hundred twenty-three".