640386450 has 216 divisors, whose sum is σ = 1993882800. Its totient is φ = 146836800.

The previous prime is 640386449. The next prime is 640386463. The reversal of 640386450 is 54683046.

640386450 is a `hidden beast` number, since 6 + 4 + 0 + 3 + 8 + 645 + 0 = 666.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 1034241 + ... + 1034859.

Almost surely, 2^640386450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640386450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (996941400).

640386450 is an abundant number, since it is smaller than the sum of its proper divisors (1353496350).

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

640386450 is a wasteful number, since it uses less digits than its factorization.

640386450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678 (or 659 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 640386450 is about 25305.8580174631. The cubic root of 640386450 is about 861.9472955468.

The spelling of 640386450 in words is "six hundred forty million, three hundred eighty-six thousand, four hundred fifty".