19931309 has 2 divisors, whose sum is σ = 19931310. Its totient is φ = 19931308.

The previous prime is 19931299. The next prime is 19931347. The reversal of 19931309 is 90313991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10259209 + 9672100 = 3203^2 + 3110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19931309 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19931369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9965654 + 9965655.

It is an arithmetic number, because the mean of its divisors is an integer number (9965655).

Almost surely, 2^19931309 is an apocalyptic number.

It is an amenable number.

19931309 is a deficient number, since it is larger than the sum of its proper divisors (1).

19931309 is an equidigital number, since it uses as much as digits as its factorization.

19931309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6561, while the sum is 35.

The square root of 19931309 is about 4464.4494621398. The cubic root of 19931309 is about 271.1306451045.

The spelling of 19931309 in words is "nineteen million, nine hundred thirty-one thousand, three hundred nine".