640854387 has 6 divisors (see below), whose sum is σ = 925678572. Its totient is φ = 427236252.

The previous prime is 640854337. The next prime is 640854407. The reversal of 640854387 is 783458046.

640854387 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640854387 - 2¹¹ = 640852339 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640854337) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35603013 + ... + 35603030.

It is an arithmetic number, because the mean of its divisors is an integer number (154279762).

Almost surely, 2^640854387 is an apocalyptic number.

640854387 is a deficient number, since it is larger than the sum of its proper divisors (284824185).

640854387 is a wasteful number, since it uses less digits than its factorization.

640854387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71206049 (or 71206046 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 45.

The square root of 640854387 is about 25315.1019551571. The cubic root of 640854387 is about 862.1571890315.

The spelling of 640854387 in words is "six hundred forty million, eight hundred fifty-four thousand, three hundred eighty-seven".