261564916 has 12 divisors (see below), whose sum is σ = 459369540. Its totient is φ = 130316480.

The previous prime is 261564893. The next prime is 261564929. The reversal of 261564916 is 619465162.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 214505316 + 47059600 = 14646^2 + 6860^2 .

It is a congruent number.

It is an unprimeable number.

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, 115231 + ... + 117478.

It is an arithmetic number, because the mean of its divisors is an integer number (38280795).

Almost surely, 2^261564916 is an apocalyptic number.

It is an amenable number.

261564916 is a deficient number, since it is larger than the sum of its proper divisors (197804624).

261564916 is a wasteful number, since it uses less digits than its factorization.

261564916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232994 (or 232992 counting only the distinct ones).

The product of its digits is 77760, while the sum is 40.

The square root of 261564916 is about 16172.9686823415. The cubic root of 261564916 is about 639.5283927989.

The spelling of 261564916 in words is "two hundred sixty-one million, five hundred sixty-four thousand, nine hundred sixteen".