138889291 has 2 divisors, whose sum is σ = 138889292. Its totient is φ = 138889290.

The previous prime is 138889237. The next prime is 138889301. The reversal of 138889291 is 192988831.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138889291 is a prime.

It is not a weakly prime, because it can be changed into another prime (138889691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69444645 + 69444646.

It is an arithmetic number, because the mean of its divisors is an integer number (69444646).

Almost surely, 2^138889291 is an apocalyptic number.

138889291 is a deficient number, since it is larger than the sum of its proper divisors (1).

138889291 is an equidigital number, since it uses as much as digits as its factorization.

138889291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 248832, while the sum is 49.

The square root of 138889291 is about 11785.1300798931. The cubic root of 138889291 is about 517.8725841062.

The spelling of 138889291 in words is "one hundred thirty-eight million, eight hundred eighty-nine thousand, two hundred ninety-one".