640338969 has 8 divisors (see below), whose sum is σ = 898721440. Its totient is φ = 404424576.

The previous prime is 640338917. The next prime is 640338971. The reversal of 640338969 is 969833046.

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

It is not a de Polignac number, because 640338969 - 2⁷ = 640338841 is a prime.

It is a super-2 number, since 2×640338969² = 820067990439965922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640338869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5616952 + ... + 5617065.

It is an arithmetic number, because the mean of its divisors is an integer number (112340180).

Almost surely, 2^640338969 is an apocalyptic number.

It is an amenable number.

640338969 is a deficient number, since it is larger than the sum of its proper divisors (258382471).

640338969 is a wasteful number, since it uses less digits than its factorization.

640338969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11234039.

The product of its (nonzero) digits is 839808, while the sum is 48.

The square root of 640338969 is about 25304.9198576087. The cubic root of 640338969 is about 861.9259921963.

The spelling of 640338969 in words is "six hundred forty million, three hundred thirty-eight thousand, nine hundred sixty-nine".