640919601 has 64 divisors (see below), whose sum is σ = 1175961600. Its totient is φ = 336607488.

The previous prime is 640919599. The next prime is 640919623. The reversal of 640919601 is 106919046.

640919601 is a `hidden beast` number, since 6 + 40 + 9 + 1 + 9 + 601 = 666.

It is not a de Polignac number, because 640919601 - 2¹ = 640919599 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640919641) 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 63 ways as a sum of consecutive naturals, for example, 135840 + ... + 140478.

It is an arithmetic number, because the mean of its divisors is an integer number (18374400).

Almost surely, 2^640919601 is an apocalyptic number.

It is an amenable number.

640919601 is a deficient number, since it is larger than the sum of its proper divisors (535041999).

640919601 is a wasteful number, since it uses less digits than its factorization.

640919601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4715 (or 4709 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 640919601 is about 25316.3899677659. The cubic root of 640919601 is about 862.1864327063.

The spelling of 640919601 in words is "six hundred forty million, nine hundred nineteen thousand, six hundred one".