9781243666 has 16 divisors (see below), whose sum is σ = 14707105920. Its totient is φ = 4878890640.

The previous prime is 9781243639. The next prime is 9781243687. The reversal of 9781243666 is 6663421879.

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, 1632396 + ... + 1638376.

It is an arithmetic number, because the mean of its divisors is an integer number (919194120).

Almost surely, 2^9781243666 is an apocalyptic number.

9781243666 is a deficient number, since it is larger than the sum of its proper divisors (4925862254).

9781243666 is a wasteful number, since it uses less digits than its factorization.

9781243666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7809.

The product of its digits is 2612736, while the sum is 52.

The square root of 9781243666 is about 98900.1702020780. The cubic root of 9781243666 is about 2138.6088482288.

The spelling of 9781243666 in words is "nine billion, seven hundred eighty-one million, two hundred forty-three thousand, six hundred sixty-six".