9640391566 has 32 divisors (see below), whose sum is σ = 15844985856. Its totient is φ = 4371840000.

The previous prime is 9640391561. The next prime is 9640391581. The reversal of 9640391566 is 6651930469.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9640391561) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1822846 + ... + 1828126.

It is an arithmetic number, because the mean of its divisors is an integer number (495155808).

Almost surely, 2^9640391566 is an apocalyptic number.

9640391566 is a deficient number, since it is larger than the sum of its proper divisors (6204594290).

9640391566 is a wasteful number, since it uses less digits than its factorization.

9640391566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6508.

The product of its (nonzero) digits is 1049760, while the sum is 49.

The square root of 9640391566 is about 98185.4957007398. The cubic root of 9640391566 is about 2128.2936929465.

The spelling of 9640391566 in words is "nine billion, six hundred forty million, three hundred ninety-one thousand, five hundred sixty-six".