261983808 has 140 divisors (see below), whose sum is σ = 786114252. Its totient is φ = 86261760.

The previous prime is 261983803. The next prime is 261983819. The reversal of 261983808 is 808389162.

261983808 is a `hidden beast` number, since 261 + 9 + 8 + 380 + 8 = 666.

261983808 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 95883264 + 166100544 = 9792^2 + 12888^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261983803) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 502588 + ... + 503108.

Almost surely, 2^261983808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261983808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (393057126).

261983808 is an abundant number, since it is smaller than the sum of its proper divisors (524130444).

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

261983808 is an equidigital number, since it uses as much as digits as its factorization.

261983808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642 (or 623 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 45.

The square root of 261983808 is about 16185.9138759602. The cubic root of 261983808 is about 639.8696088531.

The spelling of 261983808 in words is "two hundred sixty-one million, nine hundred eighty-three thousand, eight hundred eight".