261244566 has 144 divisors (see below), whose sum is σ = 672235200. Its totient is φ = 73038240.

The previous prime is 261244553. The next prime is 261244567. The reversal of 261244566 is 665442162.

261244566 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 261244566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261244567) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2441485 + ... + 2441591.

It is an arithmetic number, because the mean of its divisors is an integer number (4668300).

Almost surely, 2^261244566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261244566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (336117600).

261244566 is an abundant number, since it is smaller than the sum of its proper divisors (410990634).

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

261244566 is a wasteful number, since it uses less digits than its factorization.

261244566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 201 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 261244566 is about 16163.0617767798. The cubic root of 261244566 is about 639.2672000012.

The spelling of 261244566 in words is "two hundred sixty-one million, two hundred forty-four thousand, five hundred sixty-six".