638355384845 has 16 divisors (see below), whose sum is σ = 773936166960. Its totient is φ = 505415424000.

The previous prime is 638355384841. The next prime is 638355384847. The reversal of 638355384845 is 548483553836.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 19864365481 + 618491019364 = 140941^2 + 786442^2 .

It is not a de Polignac number, because 638355384845 - 2² = 638355384841 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638355384841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 941885 + ... + 1471005.

It is an arithmetic number, because the mean of its divisors is an integer number (48371010435).

Almost surely, 2^638355384845 is an apocalyptic number.

It is an amenable number.

638355384845 is a deficient number, since it is larger than the sum of its proper divisors (135580782115).

638355384845 is a wasteful number, since it uses less digits than its factorization.

638355384845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 531616.

The product of its digits is 165888000, while the sum is 62.

The spelling of 638355384845 in words is "six hundred thirty-eight billion, three hundred fifty-five million, three hundred eighty-four thousand, eight hundred forty-five".