138788987 has 4 divisors (see below), whose sum is σ = 140690280. Its totient is φ = 136887696.

The previous prime is 138788981. The next prime is 138788989. The reversal of 138788987 is 789887831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789887831 = 3469 ⋅227699.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138788987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138788981) 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, 950537 + ... + 950682.

It is an arithmetic number, because the mean of its divisors is an integer number (35172570).

Almost surely, 2^138788987 is an apocalyptic number.

138788987 is a deficient number, since it is larger than the sum of its proper divisors (1901293).

138788987 is an equidigital number, since it uses as much as digits as its factorization.

138788987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1901292.

The product of its digits is 5419008, while the sum is 59.

The square root of 138788987 is about 11780.8737791388. The cubic root of 138788987 is about 517.7478871842.

The spelling of 138788987 in words is "one hundred thirty-eight million, seven hundred eighty-eight thousand, nine hundred eighty-seven".