640786600 has 24 divisors (see below), whose sum is σ = 1489829310. Its totient is φ = 256314560.

The previous prime is 640786591. The next prime is 640786607. The reversal of 640786600 is 6687046.

It can be written as a sum of positive squares in 3 ways, for example, as 449185636 + 191600964 = 21194^2 + 13842^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 640786600.

It is not an unprimeable number, because it can be changed into a prime (640786607) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 1601767 + ... + 1602166.

Almost surely, 2^640786600 is an apocalyptic number.

It is an amenable number.

640786600 is an abundant number, since it is smaller than the sum of its proper divisors (849042710).

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

640786600 is a wasteful number, since it uses less digits than its factorization.

640786600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3203949 (or 3203940 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 640786600 is about 25313.7630549075. The cubic root of 640786600 is about 862.1267894528.

The spelling of 640786600 in words is "six hundred forty million, seven hundred eighty-six thousand, six hundred".