138323987 has 4 divisors (see below), whose sum is σ = 138350520. Its totient is φ = 138297456.

The previous prime is 138323981. The next prime is 138323993. The reversal of 138323987 is 789323831.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (138323981) and next prime (138323993).

It is a cyclic number.

It is not a de Polignac number, because 138323987 - 2⁶ = 138323923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138323981) 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, 2573 + ... + 16830.

It is an arithmetic number, because the mean of its divisors is an integer number (34587630).

Almost surely, 2^138323987 is an apocalyptic number.

138323987 is a deficient number, since it is larger than the sum of its proper divisors (26533).

138323987 is an equidigital number, since it uses as much as digits as its factorization.

138323987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26532.

The product of its digits is 217728, while the sum is 44.

The square root of 138323987 is about 11761.1218427495. The cubic root of 138323987 is about 517.1690176648.

The spelling of 138323987 in words is "one hundred thirty-eight million, three hundred twenty-three thousand, nine hundred eighty-seven".