261871580 has 24 divisors (see below), whose sum is σ = 550711392. Its totient is φ = 104599872.

The previous prime is 261871567. The next prime is 261871613. The reversal of 261871580 is 85178162.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5729 + ... + 23591.

It is an arithmetic number, because the mean of its divisors is an integer number (22946308).

Almost surely, 2^261871580 is an apocalyptic number.

261871580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261871580 is an abundant number, since it is smaller than the sum of its proper divisors (288839812).

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

261871580 is a wasteful number, since it uses less digits than its factorization.

261871580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18605 (or 18603 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 38.

The square root of 261871580 is about 16182.4466629741. The cubic root of 261871580 is about 639.7782271966.

The spelling of 261871580 in words is "two hundred sixty-one million, eight hundred seventy-one thousand, five hundred eighty".