261315566 has 8 divisors (see below), whose sum is σ = 393312024. Its totient is φ = 130211560.

The previous prime is 261315559. The next prime is 261315679. The reversal of 261315566 is 665513162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222380 + ... + 223551.

It is an arithmetic number, because the mean of its divisors is an integer number (49164003).

Almost surely, 2^261315566 is an apocalyptic number.

261315566 is a deficient number, since it is larger than the sum of its proper divisors (131996458).

261315566 is a wasteful number, since it uses less digits than its factorization.

261315566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 446226.

The product of its digits is 32400, while the sum is 35.

The square root of 261315566 is about 16165.2579936109. The cubic root of 261315566 is about 639.3251072472.

The spelling of 261315566 in words is "two hundred sixty-one million, three hundred fifteen thousand, five hundred sixty-six".