261143566 has 8 divisors (see below), whose sum is σ = 404351424. Its totient is φ = 126359760.

The previous prime is 261143563. The next prime is 261143567. The reversal of 261143566 is 665341162.

261143566 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261143563) 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, 2105935 + ... + 2106058.

It is an arithmetic number, because the mean of its divisors is an integer number (50543928).

Almost surely, 2^261143566 is an apocalyptic number.

261143566 is a deficient number, since it is larger than the sum of its proper divisors (143207858).

261143566 is a wasteful number, since it uses less digits than its factorization.

261143566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4212026.

The product of its digits is 25920, while the sum is 34.

The square root of 261143566 is about 16159.9370667091. The cubic root of 261143566 is about 639.1848068238.

The spelling of 261143566 in words is "two hundred sixty-one million, one hundred forty-three thousand, five hundred sixty-six".