261661662 has 48 divisors (see below), whose sum is σ = 595969920. Its totient is φ = 82809936.

The previous prime is 261661649. The next prime is 261661721. The reversal of 261661662 is 266166162.

It is a happy number.

261661662 is a `hidden beast` number, since 26 + 16 + 616 + 6 + 2 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 55273 + ... + 59819.

It is an arithmetic number, because the mean of its divisors is an integer number (12416040).

Almost surely, 2^261661662 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261661662, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (297984960).

261661662 is an abundant number, since it is smaller than the sum of its proper divisors (334308258).

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

261661662 is a wasteful number, since it uses less digits than its factorization.

261661662 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4717 (or 4714 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 261661662 is about 16175.9593842220. The cubic root of 261661662 is about 639.6072313375.

The spelling of 261661662 in words is "two hundred sixty-one million, six hundred sixty-one thousand, six hundred sixty-two".