261587680 has 24 divisors (see below), whose sum is σ = 618001272. Its totient is φ = 104635008.

The previous prime is 261587659. The next prime is 261587681. The reversal of 261587680 is 86785162.

261587680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×261587680² = 136856228655564800, which contains 22 as substring.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261587681) 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, 817302 + ... + 817621.

It is an arithmetic number, because the mean of its divisors is an integer number (25750053).

Almost surely, 2^261587680 is an apocalyptic number.

261587680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261587680 is an abundant number, since it is smaller than the sum of its proper divisors (356413592).

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

261587680 is a wasteful number, since it uses less digits than its factorization.

261587680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1634938 (or 1634930 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 43.

The square root of 261587680 is about 16173.6724339279. The cubic root of 261587680 is about 639.5469449837.

The spelling of 261587680 in words is "two hundred sixty-one million, five hundred eighty-seven thousand, six hundred eighty".