261281860 has 48 divisors (see below), whose sum is σ = 628024320. Its totient is φ = 89447040.

The previous prime is 261281833. The next prime is 261281873. The reversal of 261281860 is 68182162.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 147661 + ... + 149419.

It is an arithmetic number, because the mean of its divisors is an integer number (13083840).

Almost surely, 2^261281860 is an apocalyptic number.

261281860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261281860 is an abundant number, since it is smaller than the sum of its proper divisors (366742460).

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

261281860 is a wasteful number, since it uses less digits than its factorization.

261281860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2836 (or 2834 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 261281860 is about 16164.2154155406. The cubic root of 261281860 is about 639.2976181096.

The spelling of 261281860 in words is "two hundred sixty-one million, two hundred eighty-one thousand, eight hundred sixty".