640378000 has 160 divisors (see below), whose sum is σ = 1637082720. Its totient is φ = 241920000.

The previous prime is 640377979. The next prime is 640378001. The reversal of 640378000 is 873046.

It can be written as a sum of positive squares in 16 ways, for example, as 638269696 + 2108304 = 25264^2 + 1452^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 640378000.

It is not an unprimeable number, because it can be changed into a prime (640378001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3537910 + ... + 3538090.

It is an arithmetic number, because the mean of its divisors is an integer number (10231767).

Almost surely, 2^640378000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640378000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (818541360).

640378000 is an abundant number, since it is smaller than the sum of its proper divisors (996704720).

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

640378000 is a wasteful number, since it uses less digits than its factorization.

640378000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294 (or 278 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 640378000 is about 25305.6910595226. The cubic root of 640378000 is about 861.9435043534.

The spelling of 640378000 in words is "six hundred forty million, three hundred seventy-eight thousand".