640911380 has 24 divisors (see below), whose sum is σ = 1346389800. Its totient is φ = 256273920.

The previous prime is 640911377. The next prime is 640911409. The reversal of 640911380 is 83119046.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 47306884 + 593604496 = 6878^2 + 24364^2 .

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 106040 + ... + 111920.

It is an arithmetic number, because the mean of its divisors is an integer number (56099575).

Almost surely, 2^640911380 is an apocalyptic number.

It is an amenable number.

640911380 is an abundant number, since it is smaller than the sum of its proper divisors (705478420).

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

640911380 is a wasteful number, since it uses less digits than its factorization.

640911380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11339 (or 11337 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 640911380 is about 25316.2276020737. The cubic root of 640911380 is about 862.1827463027.

The spelling of 640911380 in words is "six hundred forty million, nine hundred eleven thousand, three hundred eighty".