138939497 has 2 divisors, whose sum is σ = 138939498. Its totient is φ = 138939496.

The previous prime is 138939469. The next prime is 138939511. The reversal of 138939497 is 794939831.

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., 130622041 + 8317456 = 11429^2 + 2884^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138939497 is a prime.

It is a super-2 number, since 2×138939497² = 38608367653226018, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (138939197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69469748 + 69469749.

It is an arithmetic number, because the mean of its divisors is an integer number (69469749).

Almost surely, 2^138939497 is an apocalyptic number.

It is an amenable number.

138939497 is a deficient number, since it is larger than the sum of its proper divisors (1).

138939497 is an equidigital number, since it uses as much as digits as its factorization.

138939497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1469664, while the sum is 53.

The square root of 138939497 is about 11787.2599445333. The cubic root of 138939497 is about 517.9349771545.

The spelling of 138939497 in words is "one hundred thirty-eight million, nine hundred thirty-nine thousand, four hundred ninety-seven".