138544681 has 8 divisors (see below), whose sum is σ = 152331264. Its totient is φ = 124956720.

The previous prime is 138544657. The next prime is 138544697. The reversal of 138544681 is 186445831.

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 138544681 - 2¹⁵ = 138511913 is a prime.

It is a super-2 number, since 2×138544681² = 38389257266783522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138541681) 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, 48190 + ... + 50983.

It is an arithmetic number, because the mean of its divisors is an integer number (19041408).

Almost surely, 2^138544681 is an apocalyptic number.

138544681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

138544681 is a deficient number, since it is larger than the sum of its proper divisors (13786583).

138544681 is a wasteful number, since it uses less digits than its factorization.

138544681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99311.

The product of its digits is 92160, while the sum is 40.

The square root of 138544681 is about 11770.5004566501. The cubic root of 138544681 is about 517.4439168454.

The spelling of 138544681 in words is "one hundred thirty-eight million, five hundred forty-four thousand, six hundred eighty-one".