638618613 has 4 divisors (see below), whose sum is σ = 851491488. Its totient is φ = 425745740.

The previous prime is 638618593. The next prime is 638618627. The reversal of 638618613 is 316816836.

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 638618613 - 2¹⁰ = 638617589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638618663) 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, 106436433 + ... + 106436438.

It is an arithmetic number, because the mean of its divisors is an integer number (212872872).

Almost surely, 2^638618613 is an apocalyptic number.

It is an amenable number.

638618613 is a deficient number, since it is larger than the sum of its proper divisors (212872875).

638618613 is a wasteful number, since it uses less digits than its factorization.

638618613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212872874.

The product of its digits is 124416, while the sum is 42.

The square root of 638618613 is about 25270.9044753052. The cubic root of 638618613 is about 861.1534068727.

The spelling of 638618613 in words is "six hundred thirty-eight million, six hundred eighteen thousand, six hundred thirteen".