261406 has 8 divisors (see below), whose sum is σ = 405720. Its totient is φ = 126168.

The previous prime is 261389. The next prime is 261407. The reversal of 261406 is 604162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2196 + ... + 2311.

It is an arithmetic number, because the mean of its divisors is an integer number (50715).

2²⁶¹⁴⁰⁶ is an apocalyptic number.

261406 is a deficient number, since it is larger than the sum of its proper divisors (144314).

261406 is a wasteful number, since it uses less digits than its factorization.

261406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4538.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 261406 is about 511.2787889205. The cubic root of 261406 is about 63.9398849580.

Adding to 261406 its reverse (604162), we get a palindrome (865568).

The spelling of 261406 in words is "two hundred sixty-one thousand, four hundred six".