261716866 has 8 divisors (see below), whose sum is σ = 393585660. Its totient is φ = 130521648.

The previous prime is 261716857. The next prime is 261716893. The reversal of 261716866 is 668617162.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 251888641 + 9828225 = 15871^2 + 3135^2 .

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

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, 167421 + ... + 168976.

Almost surely, 2^261716866 is an apocalyptic number.

261716866 is a deficient number, since it is larger than the sum of its proper divisors (131868794).

261716866 is a wasteful number, since it uses less digits than its factorization.

261716866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336788.

The product of its digits is 145152, while the sum is 43.

The square root of 261716866 is about 16177.6656536102. The cubic root of 261716866 is about 639.6522084968.

The spelling of 261716866 in words is "two hundred sixty-one million, seven hundred sixteen thousand, eight hundred sixty-six".