138281257 has 2 divisors, whose sum is σ = 138281258. Its totient is φ = 138281256.

The previous prime is 138281243. The next prime is 138281261. The reversal of 138281257 is 752182831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 133888041 + 4393216 = 11571^2 + 2096^2 .

It is a cyclic number.

It is not a de Polignac number, because 138281257 - 2¹⁵ = 138248489 is a prime.

It is not a weakly prime, because it can be changed into another prime (138281207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69140628 + 69140629.

It is an arithmetic number, because the mean of its divisors is an integer number (69140629).

Almost surely, 2^138281257 is an apocalyptic number.

It is an amenable number.

138281257 is a deficient number, since it is larger than the sum of its proper divisors (1).

138281257 is an equidigital number, since it uses as much as digits as its factorization.

138281257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 37.

The square root of 138281257 is about 11759.3051240284. The cubic root of 138281257 is about 517.1157588663.

The spelling of 138281257 in words is "one hundred thirty-eight million, two hundred eighty-one thousand, two hundred fifty-seven".