261634280 has 16 divisors (see below), whose sum is σ = 588677220. Its totient is φ = 104653696.

The previous prime is 261634273. The next prime is 261634309. The reversal of 261634280 is 82436162.

261634280 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 252110884 + 9523396 = 15878^2 + 3086^2 .

It is a super-2 number, since 2×261634280² = 136904992942236800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3270389 + ... + 3270468.

Almost surely, 2^261634280 is an apocalyptic number.

261634280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261634280 is an abundant number, since it is smaller than the sum of its proper divisors (327042940).

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

261634280 is a wasteful number, since it uses less digits than its factorization.

261634280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6540868 (or 6540864 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 261634280 is about 16175.1129826039. The cubic root of 261634280 is about 639.5849196545.

The spelling of 261634280 in words is "two hundred sixty-one million, six hundred thirty-four thousand, two hundred eighty".