1638122338 has 4 divisors (see below), whose sum is σ = 2457183510. Its totient is φ = 819061168.

The previous prime is 1638122303. The next prime is 1638122347. The reversal of 1638122338 is 8332218361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8332218361 = 69197 ⋅120413.

It can be written as a sum of positive squares in only one way, i.e., 1606165929 + 31956409 = 40077^2 + 5653^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1638122297 and 1638122306.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409530583 + ... + 409530586.

Almost surely, 2^1638122338 is an apocalyptic number.

1638122338 is a deficient number, since it is larger than the sum of its proper divisors (819061172).

1638122338 is an equidigital number, since it uses as much as digits as its factorization.

1638122338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819061171.

The product of its digits is 41472, while the sum is 37.

The square root of 1638122338 is about 40473.7240441252. The cubic root of 1638122338 is about 1178.8234797378.

The spelling of 1638122338 in words is "one billion, six hundred thirty-eight million, one hundred twenty-two thousand, three hundred thirty-eight".