138999881 has 8 divisors (see below), whose sum is σ = 142652328. Its totient is φ = 135360000.

The previous prime is 138999869. The next prime is 138999899. The reversal of 138999881 is 188999831.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 49224256 + 89775625 = 7016^2 + 9475^2 .

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 138999881 - 2¹⁰ = 138998857 is a prime.

It is a super-2 number, since 2×138999881² = 38641933836028322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138999841) 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 7 ways as a sum of consecutive naturals, for example, 21821 + ... + 27461.

It is an arithmetic number, because the mean of its divisors is an integer number (17831541).

Almost surely, 2^138999881 is an apocalyptic number.

It is an amenable number.

138999881 is a deficient number, since it is larger than the sum of its proper divisors (3652447).

138999881 is an equidigital number, since it uses as much as digits as its factorization.

138999881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6283.

The product of its digits is 1119744, while the sum is 56.

The square root of 138999881 is about 11789.8210758264. The cubic root of 138999881 is about 518.0099989125.

The spelling of 138999881 in words is "one hundred thirty-eight million, nine hundred ninety-nine thousand, eight hundred eighty-one".