640863903 has 16 divisors (see below), whose sum is σ = 860023296. Its totient is φ = 424482240.

The previous prime is 640863889. The next prime is 640863913. The reversal of 640863903 is 309368046.

It is not a de Polignac number, because 640863903 - 2⁵ = 640863871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640863913) 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 15 ways as a sum of consecutive naturals, for example, 619875 + ... + 620907.

It is an arithmetic number, because the mean of its divisors is an integer number (53751456).

Almost surely, 2^640863903 is an apocalyptic number.

640863903 is a deficient number, since it is larger than the sum of its proper divisors (219159393).

640863903 is a wasteful number, since it uses less digits than its factorization.

640863903 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2174.

The product of its (nonzero) digits is 93312, while the sum is 39.

The square root of 640863903 is about 25315.2899055097. The cubic root of 640863903 is about 862.1614563801.

The spelling of 640863903 in words is "six hundred forty million, eight hundred sixty-three thousand, nine hundred three".