138871989 has 20 divisors (see below), whose sum is σ = 213062124. Its totient is φ = 90077184.

The previous prime is 138871987. The next prime is 138871991. The reversal of 138871989 is 989178831.

It is an interprime number because it is at equal distance from previous prime (138871987) and next prime (138871991).

It can be written as a sum of positive squares in 2 ways, for example, as 95707089 + 43164900 = 9783^2 + 6570^2 .

It is not a de Polignac number, because 138871989 - 2¹ = 138871987 is a prime.

It is a super-2 number, since 2×138871989² = 38570858657632242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138871987) 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 19 ways as a sum of consecutive naturals, for example, 20172 + ... + 26165.

Almost surely, 2^138871989 is an apocalyptic number.

It is an amenable number.

138871989 is a deficient number, since it is larger than the sum of its proper divisors (74190135).

138871989 is an equidigital number, since it uses as much as digits as its factorization.

138871989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46386 (or 46377 counting only the distinct ones).

The product of its digits is 870912, while the sum is 54.

The square root of 138871989 is about 11784.3959964013. The cubic root of 138871989 is about 517.8510787200.

It can be divided in two parts, 13887 and 1989, that added together give a square (15876 = 126²).

The spelling of 138871989 in words is "one hundred thirty-eight million, eight hundred seventy-one thousand, nine hundred eighty-nine".