138721169 has 2 divisors, whose sum is σ = 138721170. Its totient is φ = 138721168.

The previous prime is 138721159. The next prime is 138721183. The reversal of 138721169 is 961127831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135955600 + 2765569 = 11660^2 + 1663^2 .

It is a cyclic number.

It is not a de Polignac number, because 138721169 - 2⁴ = 138721153 is a prime.

It is a super-2 number, since 2×138721169² = 38487125457453122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (138721159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69360584 + 69360585.

It is an arithmetic number, because the mean of its divisors is an integer number (69360585).

Almost surely, 2^138721169 is an apocalyptic number.

It is an amenable number.

138721169 is a deficient number, since it is larger than the sum of its proper divisors (1).

138721169 is an equidigital number, since it uses as much as digits as its factorization.

138721169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 38.

The square root of 138721169 is about 11777.9951180156. The cubic root of 138721169 is about 517.6635424830.

The spelling of 138721169 in words is "one hundred thirty-eight million, seven hundred twenty-one thousand, one hundred sixty-nine".