138207728169 has 105 divisors (see below), whose sum is σ = 242601889799. Its totient is φ = 78694791840.

The previous prime is 138207728147. The next prime is 138207728179. The reversal of 138207728169 is 961827702831.

It is a happy number.

The square root of 138207728169 is 371763.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 93399305769 + 44808422400 = 305613^2 + 211680^2 .

It is not a de Polignac number, because 138207728169 - 2¹⁹ = 138207203881 is a prime.

It is a super-2 number, since 2×138207728169² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138207728179) by changing a digit.

It is a polite number, since it can be written in 104 ways as a sum of consecutive naturals, for example, 491842309 + ... + 491842589.

Almost surely, 2^138207728169 is an apocalyptic number.

138207728169 is the 371763-rd square number.

138207728169 is the 185882-nd centered octagonal number.

It is an amenable number.

138207728169 is a deficient number, since it is larger than the sum of its proper divisors (104394161630).

138207728169 is an frugal number, since it uses more digits than its factorization.

138207728169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608 (or 291 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 54.

The spelling of 138207728169 in words is "one hundred thirty-eight billion, two hundred seven million, seven hundred twenty-eight thousand, one hundred sixty-nine".