138969989 has 4 divisors (see below), whose sum is σ = 139498656. Its totient is φ = 138441324.

The previous prime is 138969967. The next prime is 138970021. The reversal of 138969989 is 989969831.

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 138969989 - 2¹⁶ = 138904453 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138969959) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263939 + ... + 264464.

It is an arithmetic number, because the mean of its divisors is an integer number (34874664).

Almost surely, 2^138969989 is an apocalyptic number.

It is an amenable number.

138969989 is a deficient number, since it is larger than the sum of its proper divisors (528667).

138969989 is an equidigital number, since it uses as much as digits as its factorization.

138969989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528666.

The product of its digits is 7558272, while the sum is 62.

The square root of 138969989 is about 11788.5533039470. The cubic root of 138969989 is about 517.9728634731.

The spelling of 138969989 in words is "one hundred thirty-eight million, nine hundred sixty-nine thousand, nine hundred eighty-nine".