640603751 has 8 divisors (see below), whose sum is σ = 669364224. Its totient is φ = 611919000.

The previous prime is 640603729. The next prime is 640603763. The reversal of 640603751 is 157306046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640603751 - 2⁶ = 640603687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640603771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1271 + ... + 35816.

It is an arithmetic number, because the mean of its divisors is an integer number (83670528).

Almost surely, 2^640603751 is an apocalyptic number.

640603751 is a deficient number, since it is larger than the sum of its proper divisors (28760473).

640603751 is a wasteful number, since it uses less digits than its factorization.

640603751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37861.

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 640603751 is about 25310.1511453409. The cubic root of 640603751 is about 862.0447787814.

Adding to 640603751 its reverse (157306046), we get a palindrome (797909797).

The spelling of 640603751 in words is "six hundred forty million, six hundred three thousand, seven hundred fifty-one".