638026778002 has 8 divisors (see below), whose sum is σ = 957138043212. Its totient is φ = 318980763600.

The previous prime is 638026777981. The next prime is 638026778029. The reversal of 638026778002 is 200877620836.

It can be written as a sum of positive squares in 2 ways, for example, as 560448374161 + 77578403841 = 748631^2 + 278529^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×638026778002² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16288249 + ... + 16327372.

Almost surely, 2^638026778002 is an apocalyptic number.

638026778002 is a deficient number, since it is larger than the sum of its proper divisors (319111265210).

638026778002 is a wasteful number, since it uses less digits than its factorization.

638026778002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32625404.

The product of its (nonzero) digits is 1354752, while the sum is 49.

The spelling of 638026778002 in words is "six hundred thirty-eight billion, twenty-six million, seven hundred seventy-eight thousand, two".