638615718007 has 4 divisors (see below), whose sum is σ = 676181348496. Its totient is φ = 601050087520.

The previous prime is 638615717983. The next prime is 638615718017. The reversal of 638615718007 is 700817516836.

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-638615718007 is a prime.

It is a super-2 number, since 2×638615718007² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638615718017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18782815219 + ... + 18782815252.

It is an arithmetic number, because the mean of its divisors is an integer number (169045337124).

Almost surely, 2^638615718007 is an apocalyptic number.

638615718007 is a deficient number, since it is larger than the sum of its proper divisors (37565630489).

638615718007 is a wasteful number, since it uses less digits than its factorization.

638615718007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37565630488.

The product of its (nonzero) digits is 1693440, while the sum is 52.

The spelling of 638615718007 in words is "six hundred thirty-eight billion, six hundred fifteen million, seven hundred eighteen thousand, seven".