138881987 has 2 divisors, whose sum is σ = 138881988. Its totient is φ = 138881986.

The previous prime is 138881927. The next prime is 138882019. The reversal of 138881987 is 789188831.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 138881987 - 2¹⁴ = 138865603 is a prime.

It is not a weakly prime, because it can be changed into another prime (138881917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69440993 + 69440994.

It is an arithmetic number, because the mean of its divisors is an integer number (69440994).

Almost surely, 2^138881987 is an apocalyptic number.

138881987 is a deficient number, since it is larger than the sum of its proper divisors (1).

138881987 is an equidigital number, since it uses as much as digits as its factorization.

138881987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 774144, while the sum is 53.

The square root of 138881987 is about 11784.8201937917. The cubic root of 138881987 is about 517.8635058741.

The spelling of 138881987 in words is "one hundred thirty-eight million, eight hundred eighty-one thousand, nine hundred eighty-seven".