261323556 has 96 divisors (see below), whose sum is σ = 678881280. Its totient is φ = 77728896.

The previous prime is 261323551. The next prime is 261323603. The reversal of 261323556 is 655323162.

261323556 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (261323551) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1093285 + ... + 1093523.

It is an arithmetic number, because the mean of its divisors is an integer number (7071680).

Almost surely, 2^261323556 is an apocalyptic number.

261323556 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261323556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (339440640).

261323556 is an abundant number, since it is smaller than the sum of its proper divisors (417557724).

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

261323556 is a wasteful number, since it uses less digits than its factorization.

261323556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465 (or 463 counting only the distinct ones).

The product of its digits is 32400, while the sum is 33.

The square root of 261323556 is about 16165.5051266578. The cubic root of 261323556 is about 639.3316231947.

The spelling of 261323556 in words is "two hundred sixty-one million, three hundred twenty-three thousand, five hundred fifty-six".