640466000 has 80 divisors (see below), whose sum is σ = 1554329088. Its totient is φ = 255248000.

The previous prime is 640465999. The next prime is 640466009. The reversal of 640466000 is 664046.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640466009) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 861629 + ... + 862371.

Almost surely, 2^640466000 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 640466000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (777164544).

640466000 is an abundant number, since it is smaller than the sum of its proper divisors (913863088).

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

640466000 is a wasteful number, since it uses less digits than its factorization.

640466000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1197 (or 1181 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 640466000 is about 25307.4297391102. The cubic root of 640466000 is about 861.9829849696.

The spelling of 640466000 in words is "six hundred forty million, four hundred sixty-six thousand".