638403257263 has 4 divisors (see below), whose sum is σ = 644984734240. Its totient is φ = 631821780288.

The previous prime is 638403257249. The next prime is 638403257279. The reversal of 638403257263 is 362752304836.

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

It is a cyclic number.

It is not a de Polignac number, because 638403257263 - 2²⁹ = 637866386351 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 (638403257203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3290738343 + ... + 3290738536.

It is an arithmetic number, because the mean of its divisors is an integer number (161246183560).

Almost surely, 2^638403257263 is an apocalyptic number.

638403257263 is a deficient number, since it is larger than the sum of its proper divisors (6581476977).

638403257263 is an equidigital number, since it uses as much as digits as its factorization.

638403257263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6581476976.

The product of its (nonzero) digits is 4354560, while the sum is 49.

The spelling of 638403257263 in words is "six hundred thirty-eight billion, four hundred three million, two hundred fifty-seven thousand, two hundred sixty-three".