261081 has 6 divisors (see below), whose sum is σ = 377130. Its totient is φ = 174048.

The previous prime is 261077. The next prime is 261089. The reversal of 261081 is 180162.

It can be written as a sum of positive squares in only one way, i.e., 176400 + 84681 = 420^2 + 291^2 .

It is not a de Polignac number, because 261081 - 2² = 261077 is a prime.

It is a super-2 number, since 2×261081² = 136326577122, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 261081.

It is not an unprimeable number, because it can be changed into a prime (261089) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14496 + ... + 14513.

It is an arithmetic number, because the mean of its divisors is an integer number (62855).

2²⁶¹⁰⁸¹ is an apocalyptic number.

It is an amenable number.

261081 is a deficient number, since it is larger than the sum of its proper divisors (116049).

261081 is a wasteful number, since it uses less digits than its factorization.

261081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29015 (or 29012 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 261081 is about 510.9608595578. The cubic root of 261081 is about 63.9133756449.

The spelling of 261081 in words is "two hundred sixty-one thousand, eighty-one".