261916 has 6 divisors (see below), whose sum is σ = 458360. Its totient is φ = 130956.

The previous prime is 261887. The next prime is 261917. The reversal of 261916 is 619162.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261917) by changing a digit.

261916 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 as a sum of consecutive naturals, namely, 32736 + ... + 32743.

2²⁶¹⁹¹⁶ is an apocalyptic number.

It is an amenable number.

261916 is a deficient number, since it is larger than the sum of its proper divisors (196444).

261916 is a wasteful number, since it uses less digits than its factorization.

261916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65483 (or 65481 counting only the distinct ones).

The product of its digits is 648, while the sum is 25.

The square root of 261916 is about 511.7772953151. Note that the first 3 decimals coincide. The cubic root of 261916 is about 63.9814399306.

The spelling of 261916 in words is "two hundred sixty-one thousand, nine hundred sixteen".