261431965 has 8 divisors (see below), whose sum is σ = 314940600. Its totient is φ = 208330752.

The previous prime is 261431953. The next prime is 261431969. The reversal of 261431965 is 569134162.

It can be written as a sum of positive squares in 4 ways, for example, as 54848836 + 206583129 = 7406^2 + 14373^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 261431965 - 2⁹ = 261431453 is a prime.

It is a super-2 number, since 2×261431965² = 136693344647522450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261431969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 100440 + ... + 103009.

It is an arithmetic number, because the mean of its divisors is an integer number (39367575).

Almost surely, 2^261431965 is an apocalyptic number.

It is an amenable number.

261431965 is a deficient number, since it is larger than the sum of its proper divisors (53508635).

261431965 is a wasteful number, since it uses less digits than its factorization.

261431965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203711.

The product of its digits is 38880, while the sum is 37.

The square root of 261431965 is about 16168.8578755582. The cubic root of 261431965 is about 639.4200190018.

The spelling of 261431965 in words is "two hundred sixty-one million, four hundred thirty-one thousand, nine hundred sixty-five".