261989868 has 72 divisors (see below), whose sum is σ = 715008000. Its totient is φ = 74444832.

The previous prime is 261989867. The next prime is 261989869. The reversal of 261989868 is 868989162.

261989868 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261989867) and next prime (261989869).

It is not an unprimeable number, because it can be changed into a prime (261989863) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 115893 + ... + 118131.

Almost surely, 2^261989868 is an apocalyptic number.

261989868 is a gapful number since it is divisible by the number (28) 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 261989868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (357504000).

261989868 is an abundant number, since it is smaller than the sum of its proper divisors (453018132).

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

261989868 is a wasteful number, since it uses less digits than its factorization.

261989868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2459 (or 2450 counting only the distinct ones).

The product of its digits is 2985984, while the sum is 57.

The square root of 261989868 is about 16186.1010746875. The cubic root of 261989868 is about 639.8745424658.

The spelling of 261989868 in words is "two hundred sixty-one million, nine hundred eighty-nine thousand, eight hundred sixty-eight".