638627863 has 4 divisors (see below), whose sum is σ = 646711840. Its totient is φ = 630543888.

The previous prime is 638627851. The next prime is 638627897. The reversal of 638627863 is 368726836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638627863 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 (638627833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4041870 + ... + 4042027.

It is an arithmetic number, because the mean of its divisors is an integer number (161677960).

Almost surely, 2^638627863 is an apocalyptic number.

638627863 is a deficient number, since it is larger than the sum of its proper divisors (8083977).

638627863 is an equidigital number, since it uses as much as digits as its factorization.

638627863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8083976.

The product of its digits is 1741824, while the sum is 49.

The square root of 638627863 is about 25271.0874914397. The cubic root of 638627863 is about 861.1575646128.

The spelling of 638627863 in words is "six hundred thirty-eight million, six hundred twenty-seven thousand, eight hundred sixty-three".