638613447077 has 4 divisors (see below), whose sum is σ = 638731430220. Its totient is φ = 638495463936.

The previous prime is 638613446987. The next prime is 638613447133. The reversal of 638613447077 is 770744316836.

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

It can be written as a sum of positive squares in 2 ways, for example, as 178602592996 + 460010854081 = 422614^2 + 678241^2 .

It is a cyclic number.

It is not a de Polignac number, because 638613447077 - 2²⁴ = 638596669861 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 (638613440077) 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, 58983452 + ... + 58994277.

It is an arithmetic number, because the mean of its divisors is an integer number (159682857555).

Almost surely, 2^638613447077 is an apocalyptic number.

It is an amenable number.

638613447077 is a deficient number, since it is larger than the sum of its proper divisors (117983143).

638613447077 is a wasteful number, since it uses less digits than its factorization.

638613447077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117983142.

The product of its (nonzero) digits is 14224896, while the sum is 56.

The spelling of 638613447077 in words is "six hundred thirty-eight billion, six hundred thirteen million, four hundred forty-seven thousand, seventy-seven".