638313663 has 16 divisors (see below), whose sum is σ = 917267456. Its totient is φ = 392502240.

The previous prime is 638313661. The next prime is 638313667. The reversal of 638313663 is 366313836.

It is not a de Polignac number, because 638313663 - 2¹ = 638313661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638313661) 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, 50778 + ... + 62088.

It is an arithmetic number, because the mean of its divisors is an integer number (57329216).

Almost surely, 2^638313663 is an apocalyptic number.

638313663 is a deficient number, since it is larger than the sum of its proper divisors (278953793).

638313663 is a wasteful number, since it uses less digits than its factorization.

638313663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12774.

The product of its digits is 139968, while the sum is 39.

The square root of 638313663 is about 25264.8701362188. The cubic root of 638313663 is about 861.0163138112.

The spelling of 638313663 in words is "six hundred thirty-eight million, three hundred thirteen thousand, six hundred sixty-three".