247666 has 4 divisors (see below), whose sum is σ = 371502. Its totient is φ = 123832.

The previous prime is 247651. The next prime is 247691. The reversal of 247666 is 666742.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 229441 + 18225 = 479^2 + 135^2 .

It is a super-2 number, since 2×247666² = 122676895112, which contains 22 as substring.

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61915 + ... + 61918.

2²⁴⁷⁶⁶⁶ is an apocalyptic number.

247666 is a deficient number, since it is larger than the sum of its proper divisors (123836).

247666 is a wasteful number, since it uses less digits than its factorization.

247666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123835.

The product of its digits is 12096, while the sum is 31.

The square root of 247666 is about 497.6605268655. The cubic root of 247666 is about 62.7993955072.

The spelling of 247666 in words is "two hundred forty-seven thousand, six hundred sixty-six".