138780869 has 2 divisors, whose sum is σ = 138780870. Its totient is φ = 138780868.

The previous prime is 138780799. The next prime is 138780913. The reversal of 138780869 is 968087831.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 131560900 + 7219969 = 11470^2 + 2687^2 .

It is a cyclic number.

It is not a de Polignac number, because 138780869 - 2²⁴ = 122003653 is a prime.

It is a super-2 number, since 2×138780869² = 38520259200790322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138785869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69390434 + 69390435.

It is an arithmetic number, because the mean of its divisors is an integer number (69390435).

Almost surely, 2^138780869 is an apocalyptic number.

It is an amenable number.

138780869 is a deficient number, since it is larger than the sum of its proper divisors (1).

138780869 is an equidigital number, since it uses as much as digits as its factorization.

138780869 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 580608, while the sum is 50.

The square root of 138780869 is about 11780.5292325939. The cubic root of 138780869 is about 517.7377923407.

The spelling of 138780869 in words is "one hundred thirty-eight million, seven hundred eighty thousand, eight hundred sixty-nine".