138681437 has 4 divisors (see below), whose sum is σ = 145980480. Its totient is φ = 131382396.

The previous prime is 138681391. The next prime is 138681469. The reversal of 138681437 is 734186831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 138681437 - 2¹⁰ = 138680413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138681394 and 138681403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138681497) 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, 3649493 + ... + 3649530.

It is an arithmetic number, because the mean of its divisors is an integer number (36495120).

Almost surely, 2^138681437 is an apocalyptic number.

It is an amenable number.

138681437 is a deficient number, since it is larger than the sum of its proper divisors (7299043).

138681437 is an equidigital number, since it uses as much as digits as its factorization.

138681437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7299042.

The product of its digits is 96768, while the sum is 41.

The square root of 138681437 is about 11776.3082924998. The cubic root of 138681437 is about 517.6141153432.

The spelling of 138681437 in words is "one hundred thirty-eight million, six hundred eighty-one thousand, four hundred thirty-seven".