640662248 has 8 divisors (see below), whose sum is σ = 1201241730. Its totient is φ = 320331120.

The previous prime is 640662233. The next prime is 640662293. The reversal of 640662248 is 842266046.

It can be written as a sum of positive squares in only one way, i.e., 572070724 + 68591524 = 23918^2 + 8282^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40041383 + ... + 40041398.

Almost surely, 2^640662248 is an apocalyptic number.

It is an amenable number.

640662248 is a deficient number, since it is larger than the sum of its proper divisors (560579482).

640662248 is a wasteful number, since it uses less digits than its factorization.

640662248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80082787 (or 80082783 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 38.

The square root of 640662248 is about 25311.3067224906. The cubic root of 640662248 is about 862.0710173095.

The spelling of 640662248 in words is "six hundred forty million, six hundred sixty-two thousand, two hundred forty-eight".