261997888 has 28 divisors (see below), whose sum is σ = 533958292. Its totient is φ = 127457280.

The previous prime is 261997847. The next prime is 261997889. The reversal of 261997888 is 888799162.

261997888 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 182574144 + 79423744 = 13512^2 + 8912^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261997889) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52953 + ... + 57688.

It is an arithmetic number, because the mean of its divisors is an integer number (19069939).

Almost surely, 2^261997888 is an apocalyptic number.

It is an amenable number.

261997888 is an abundant number, since it is smaller than the sum of its proper divisors (271960404).

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

261997888 is a wasteful number, since it uses less digits than its factorization.

261997888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110690 (or 110680 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 58.

The square root of 261997888 is about 16186.3488162093. The cubic root of 261997888 is about 639.8810716514.

The spelling of 261997888 in words is "two hundred sixty-one million, nine hundred ninety-seven thousand, eight hundred eighty-eight".