261606 has 16 divisors (see below), whose sum is σ = 532800. Its totient is φ = 85608.

The previous prime is 261601. The next prime is 261619. The reversal of 261606 is 606162.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261601) by changing a digit.

261606 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16 + ... + 723.

It is an arithmetic number, because the mean of its divisors is an integer number (33300).

2²⁶¹⁶⁰⁶ is an apocalyptic number.

261606 is an abundant number, since it is smaller than the sum of its proper divisors (271194).

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

261606 is a wasteful number, since it uses less digits than its factorization.

261606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 261606 is about 511.4743395323. The cubic root of 261606 is about 63.9561874620.

Adding to 261606 its reverse (606162), we get a palindrome (867768).

The spelling of 261606 in words is "two hundred sixty-one thousand, six hundred six".