638634506753 has 4 divisors (see below), whose sum is σ = 639153301248. Its totient is φ = 638115712260.

The previous prime is 638634506743. The next prime is 638634506761. The reversal of 638634506753 is 357605436836.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638634506753 - 2¹⁸ = 638634244609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638634506743) 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, 259395401 + ... + 259397862.

It is an arithmetic number, because the mean of its divisors is an integer number (159788325312).

Almost surely, 2^638634506753 is an apocalyptic number.

It is an amenable number.

638634506753 is a deficient number, since it is larger than the sum of its proper divisors (518794495).

638634506753 is a wasteful number, since it uses less digits than its factorization.

638634506753 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518794494.

The product of its (nonzero) digits is 32659200, while the sum is 56.

The spelling of 638634506753 in words is "six hundred thirty-eight billion, six hundred thirty-four million, five hundred six thousand, seven hundred fifty-three".