138756251 has 4 divisors (see below), whose sum is σ = 140315400. Its totient is φ = 137197104.

The previous prime is 138756199. The next prime is 138756257. The reversal of 138756251 is 152657831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 152657831 = 23 ⋅6637297.

It is a cyclic number.

It is not a de Polignac number, because 138756251 - 2⁶ = 138756187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138756257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 779441 + ... + 779618.

It is an arithmetic number, because the mean of its divisors is an integer number (35078850).

Almost surely, 2^138756251 is an apocalyptic number.

138756251 is a deficient number, since it is larger than the sum of its proper divisors (1559149).

138756251 is an equidigital number, since it uses as much as digits as its factorization.

138756251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1559148.

The product of its digits is 50400, while the sum is 38.

The square root of 138756251 is about 11779.4843265739. The cubic root of 138756251 is about 517.7071771155.

The spelling of 138756251 in words is "one hundred thirty-eight million, seven hundred fifty-six thousand, two hundred fifty-one".