138641257 has 8 divisors (see below), whose sum is σ = 147299400. Its totient is φ = 130241664.

The previous prime is 138641231. The next prime is 138641267. The reversal of 138641257 is 752146831.

It can be written as a sum of positive squares in 4 ways, for example, as 13111641 + 125529616 = 3621^2 + 11204^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 138641257 - 2¹⁵ = 138608489 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138641267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63532 + ... + 65677.

It is an arithmetic number, because the mean of its divisors is an integer number (18412425).

Almost surely, 2^138641257 is an apocalyptic number.

It is an amenable number.

138641257 is a deficient number, since it is larger than the sum of its proper divisors (8658143).

138641257 is a wasteful number, since it uses less digits than its factorization.

138641257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129275.

The product of its digits is 40320, while the sum is 37.

The square root of 138641257 is about 11774.6022013485. The cubic root of 138641257 is about 517.5641212837.

The spelling of 138641257 in words is "one hundred thirty-eight million, six hundred forty-one thousand, two hundred fifty-seven".