640346240 has 32 divisors (see below), whose sum is σ = 1530829260. Its totient is φ = 256138240.

The previous prime is 640346233. The next prime is 640346249. The reversal of 640346240 is 42643046.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 640292416 + 53824 = 25304^2 + 232^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (640346249) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 499631 + ... + 500910.

Almost surely, 2^640346240 is an apocalyptic number.

It is an amenable number.

640346240 is an abundant number, since it is smaller than the sum of its proper divisors (890483020).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640346240 is a wasteful number, since it uses less digits than its factorization.

640346240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000560 (or 1000548 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 640346240 is about 25305.0635249153. The cubic root of 640346240 is about 861.9292545518.

Adding to 640346240 its reverse (42643046), we get a palindrome (682989286).

The spelling of 640346240 in words is "six hundred forty million, three hundred forty-six thousand, two hundred forty".