139694987 has 2 divisors, whose sum is σ = 139694988. Its totient is φ = 139694986.

The previous prime is 139694983. The next prime is 139694993. The reversal of 139694987 is 789496931.

It is a weak prime.

It is an emirp because it is prime and its reverse (789496931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 139694987 - 2² = 139694983 is a prime.

It is not a weakly prime, because it can be changed into another prime (139694983) 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, 69847493 + 69847494.

It is an arithmetic number, because the mean of its divisors is an integer number (69847494).

Almost surely, 2^139694987 is an apocalyptic number.

139694987 is a deficient number, since it is larger than the sum of its proper divisors (1).

139694987 is an equidigital number, since it uses as much as digits as its factorization.

139694987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2939328, while the sum is 56.

The square root of 139694987 is about 11819.2633865229. The cubic root of 139694987 is about 518.8720459538.

The spelling of 139694987 in words is "one hundred thirty-nine million, six hundred ninety-four thousand, nine hundred eighty-seven".