138509957 has 2 divisors, whose sum is σ = 138509958. Its totient is φ = 138509956.

The previous prime is 138509951. The next prime is 138510007. The reversal of 138509957 is 759905831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 105493441 + 33016516 = 10271^2 + 5746^2 .

It is a cyclic number.

It is not a de Polignac number, because 138509957 - 2¹⁴ = 138493573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138509951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69254978 + 69254979.

It is an arithmetic number, because the mean of its divisors is an integer number (69254979).

Almost surely, 2^138509957 is an apocalyptic number.

It is an amenable number.

138509957 is a deficient number, since it is larger than the sum of its proper divisors (1).

138509957 is an equidigital number, since it uses as much as digits as its factorization.

138509957 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 340200, while the sum is 47.

The square root of 138509957 is about 11769.0253207307. The cubic root of 138509957 is about 517.4006835632.

The spelling of 138509957 in words is "one hundred thirty-eight million, five hundred nine thousand, nine hundred fifty-seven".