261324666 has 48 divisors (see below), whose sum is σ = 596344320. Its totient is φ = 82542240.

The previous prime is 261324647. The next prime is 261324703. The reversal of 261324666 is 666423162.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 261324666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42231 + ... + 48021.

It is an arithmetic number, because the mean of its divisors is an integer number (12423840).

Almost surely, 2^261324666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261324666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (298172160).

261324666 is an abundant number, since it is smaller than the sum of its proper divisors (335019654).

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

261324666 is a wasteful number, since it uses less digits than its factorization.

261324666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5931 (or 5928 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 261324666 is about 16165.5394589850. The cubic root of 261324666 is about 639.3325284035.

The spelling of 261324666 in words is "two hundred sixty-one million, three hundred twenty-four thousand, six hundred sixty-six".