261665296 has 40 divisors (see below), whose sum is σ = 546107904. Its totient is φ = 121102080.

The previous prime is 261665269. The next prime is 261665297. The reversal of 261665296 is 692566162.

It is not an unprimeable number, because it can be changed into a prime (261665297) 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, 61 + ... + 22876.

Almost surely, 2^261665296 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261665296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (273053952).

261665296 is an abundant number, since it is smaller than the sum of its proper divisors (284442608).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261665296 is a wasteful number, since it uses less digits than its factorization.

261665296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22999 (or 22993 counting only the distinct ones).

The product of its digits is 233280, while the sum is 43.

The square root of 261665296 is about 16176.0717110181. The cubic root of 261665296 is about 639.6101923138.

The spelling of 261665296 in words is "two hundred sixty-one million, six hundred sixty-five thousand, two hundred ninety-six".