261040 has 40 divisors (see below), whose sum is σ = 656208. Its totient is φ = 96000.

The previous prime is 261031. The next prime is 261043. The reversal of 261040 is 40162.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 261040.

It is not an unprimeable number, because it can be changed into a prime (261043) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 915 + ... + 1165.

2²⁶¹⁰⁴⁰ is an apocalyptic number.

261040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (328104).

261040 is an abundant number, since it is smaller than the sum of its proper divisors (395168).

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

261040 is a wasteful number, since it uses less digits than its factorization.

261040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277 (or 271 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 261040 is about 510.9207374926. The cubic root of 261040 is about 63.9100298307.

The spelling of 261040 in words is "two hundred sixty-one thousand, forty".