261566356 has 12 divisors (see below), whose sum is σ = 460066068. Its totient is φ = 130118912.

The previous prime is 261566351. The next prime is 261566381. The reversal of 261566356 is 653665162.

It is a happy number.

261566356 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 233050756 + 28515600 = 15266^2 + 5340^2 .

It is a super-2 number, since 2×261566356² = 136833917182237472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261566351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165181 + ... + 166756.

It is an arithmetic number, because the mean of its divisors is an integer number (38338839).

Almost surely, 2^261566356 is an apocalyptic number.

It is an amenable number.

261566356 is a deficient number, since it is larger than the sum of its proper divisors (198499712).

261566356 is a wasteful number, since it uses less digits than its factorization.

261566356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332138 (or 332136 counting only the distinct ones).

The product of its digits is 194400, while the sum is 40.

The square root of 261566356 is about 16173.0132010086. The cubic root of 261566356 is about 639.5295664007.

The spelling of 261566356 in words is "two hundred sixty-one million, five hundred sixty-six thousand, three hundred fifty-six".