2172538138 has 4 divisors (see below), whose sum is σ = 3258807210. Its totient is φ = 1086269068.

The previous prime is 2172538133. The next prime is 2172538177. The reversal of 2172538138 is 8318352712.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 1163014609 + 1009523529 = 34103^2 + 31773^2 .

It is a super-2 number, since 2×2172538138² = 9439843922129014088, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2172538138.

It is not an unprimeable number, because it can be changed into a prime (2172538133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 543134533 + ... + 543134536.

Almost surely, 2^2172538138 is an apocalyptic number.

2172538138 is a deficient number, since it is larger than the sum of its proper divisors (1086269072).

2172538138 is a wasteful number, since it uses less digits than its factorization.

2172538138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1086269071.

The product of its digits is 80640, while the sum is 40.

The square root of 2172538138 is about 46610.4938613613. The cubic root of 2172538138 is about 1295.1571566799.

It can be divided in two parts, 2172538 and 138, that added together give a square (2172676 = 1474²).

The spelling of 2172538138 in words is "two billion, one hundred seventy-two million, five hundred thirty-eight thousand, one hundred thirty-eight".