261765 has 32 divisors (see below), whose sum is σ = 533760. Its totient is φ = 119232.

The previous prime is 261761. The next prime is 261773. The reversal of 261765 is 567162.

It is not a de Polignac number, because 261765 - 2² = 261761 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 261765.

It is not an unprimeable number, because it can be changed into a prime (261761) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 807 + ... + 1083.

It is an arithmetic number, because the mean of its divisors is an integer number (16680).

2²⁶¹⁷⁶⁵ is an apocalyptic number.

It is an amenable number.

261765 is an abundant number, since it is smaller than the sum of its proper divisors (271995).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261765 is a wasteful number, since it uses less digits than its factorization.

261765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298 (or 292 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 261765 is about 511.6297489396. The cubic root of 261765 is about 63.9691420251.

The spelling of 261765 in words is "two hundred sixty-one thousand, seven hundred sixty-five".