138618881 has 8 divisors (see below), whose sum is σ = 140657664. Its totient is φ = 136589040.

The previous prime is 138618863. The next prime is 138618899. The reversal of 138618881 is 188816831.

It is an interprime number because it is at equal distance from previous prime (138618863) and next prime (138618899).

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 138618881 - 2⁶ = 138618817 is a prime.

It is a super-2 number, since 2×138618881² = 38430388339384322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138618841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32960 + ... + 36926.

It is an arithmetic number, because the mean of its divisors is an integer number (17582208).

Almost surely, 2^138618881 is an apocalyptic number.

It is an amenable number.

138618881 is a deficient number, since it is larger than the sum of its proper divisors (2038783).

138618881 is an equidigital number, since it uses as much as digits as its factorization.

138618881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4471.

The product of its digits is 73728, while the sum is 44.

The square root of 138618881 is about 11773.6519822865. The cubic root of 138618881 is about 517.5362757055.

The spelling of 138618881 in words is "one hundred thirty-eight million, six hundred eighteen thousand, eight hundred eighty-one".