640933243 has 4 divisors (see below), whose sum is σ = 640984248. Its totient is φ = 640882240.

The previous prime is 640933229. The next prime is 640933253. The reversal of 640933243 is 342339046.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 640933243 - 2²¹ = 638836091 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640933199 and 640933208.

It is not an unprimeable number, because it can be changed into a prime (640933253) 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 3 ways as a sum of consecutive naturals, for example, 8148 + ... + 36718.

It is an arithmetic number, because the mean of its divisors is an integer number (160246062).

Almost surely, 2^640933243 is an apocalyptic number.

640933243 is a deficient number, since it is larger than the sum of its proper divisors (51005).

640933243 is a wasteful number, since it uses less digits than its factorization.

640933243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51004.

The product of its (nonzero) digits is 46656, while the sum is 34.

The square root of 640933243 is about 25316.6593965318. The cubic root of 640933243 is about 862.1925498875.

The spelling of 640933243 in words is "six hundred forty million, nine hundred thirty-three thousand, two hundred forty-three".