138537251 has 4 divisors (see below), whose sum is σ = 140885400. Its totient is φ = 136189104.

The previous prime is 138537241. The next prime is 138537281. The reversal of 138537251 is 152735831.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 138537251 - 2⁶ = 138537187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138537221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1173986 + ... + 1174103.

It is an arithmetic number, because the mean of its divisors is an integer number (35221350).

Almost surely, 2^138537251 is an apocalyptic number.

138537251 is a deficient number, since it is larger than the sum of its proper divisors (2348149).

138537251 is an equidigital number, since it uses as much as digits as its factorization.

138537251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2348148.

The product of its digits is 25200, while the sum is 35.

The square root of 138537251 is about 11770.1848328733. The cubic root of 138537251 is about 517.4346666959.

The spelling of 138537251 in words is "one hundred thirty-eight million, five hundred thirty-seven thousand, two hundred fifty-one".