137891309 has 2 divisors, whose sum is σ = 137891310. Its totient is φ = 137891308.

The previous prime is 137891287. The next prime is 137891311. The reversal of 137891309 is 903198731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 84235684 + 53655625 = 9178^2 + 7325^2 .

It is a cyclic number.

It is not a de Polignac number, because 137891309 - 2⁸ = 137891053 is a prime.

Together with 137891311, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (137891329) 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, 68945654 + 68945655.

It is an arithmetic number, because the mean of its divisors is an integer number (68945655).

Almost surely, 2^137891309 is an apocalyptic number.

It is an amenable number.

137891309 is a deficient number, since it is larger than the sum of its proper divisors (1).

137891309 is an equidigital number, since it uses as much as digits as its factorization.

137891309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 137891309 is about 11742.7130170161. The cubic root of 137891309 is about 516.6292188375.

The spelling of 137891309 in words is "one hundred thirty-seven million, eight hundred ninety-one thousand, three hundred nine".