261516580 has 24 divisors (see below), whose sum is σ = 591430392. Its totient is φ = 96559872.

The previous prime is 261516557. The next prime is 261516599. The reversal of 261516580 is 85615162.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1597696 + 259918884 = 1264^2 + 16122^2 .

It is a super-2 number, since 2×261516580² = 136781843229792800, which contains 22 as substring.

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, 502657 + ... + 503176.

It is an arithmetic number, because the mean of its divisors is an integer number (24642933).

Almost surely, 2^261516580 is an apocalyptic number.

261516580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261516580 is an abundant number, since it is smaller than the sum of its proper divisors (329913812).

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

261516580 is a wasteful number, since it uses less digits than its factorization.

261516580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1005855 (or 1005853 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 261516580 is about 16171.4742679819. The cubic root of 261516580 is about 639.4889963982.

The spelling of 261516580 in words is "two hundred sixty-one million, five hundred sixteen thousand, five hundred eighty".