261568664 has 48 divisors (see below), whose sum is σ = 604088280. Its totient is φ = 105504000.

The previous prime is 261568663. The next prime is 261568667. The reversal of 261568664 is 466865162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261568663) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12962 + ... + 26289.

Almost surely, 2^261568664 is an apocalyptic number.

It is an amenable number.

261568664 is an abundant number, since it is smaller than the sum of its proper divisors (342519616).

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

261568664 is a wasteful number, since it uses less digits than its factorization.

261568664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39288 (or 39277 counting only the distinct ones).

The product of its digits is 414720, while the sum is 44.

The square root of 261568664 is about 16173.0845542834. The cubic root of 261568664 is about 639.5314474147.

The spelling of 261568664 in words is "two hundred sixty-one million, five hundred sixty-eight thousand, six hundred sixty-four".