261616 has 20 divisors (see below), whose sum is σ = 515592. Its totient is φ = 128576.

The previous prime is 261601. The next prime is 261619. The reversal of 261616 is 616162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261619) 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, 1230 + ... + 1426.

2²⁶¹⁶¹⁶ is an apocalyptic number.

It is an amenable number.

261616 is a deficient number, since it is larger than the sum of its proper divisors (253976).

261616 is a wasteful number, since it uses less digits than its factorization.

261616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288 (or 282 counting only the distinct ones).

The product of its digits is 432, while the sum is 22.

The square root of 261616 is about 511.4841151004. The cubic root of 261616 is about 63.9570023690.

Adding to 261616 its reverse (616162), we get a palindrome (877778).

The spelling of 261616 in words is "two hundred sixty-one thousand, six hundred sixteen".