19993709 has 2 divisors, whose sum is σ = 19993710. Its totient is φ = 19993708.

The previous prime is 19993669. The next prime is 19993723. The reversal of 19993709 is 90739991.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19096900 + 896809 = 4370^2 + 947^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19993709 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 (19983709) 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, 9996854 + 9996855.

It is an arithmetic number, because the mean of its divisors is an integer number (9996855).

Almost surely, 2^19993709 is an apocalyptic number.

It is an amenable number.

19993709 is a deficient number, since it is larger than the sum of its proper divisors (1).

19993709 is an equidigital number, since it uses as much as digits as its factorization.

19993709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 137781, while the sum is 47.

The square root of 19993709 is about 4471.4325444985. The cubic root of 19993709 is about 271.4132980062.

It can be divided in two parts, 19993 and 709, that added together give a palindrome (20702).

The spelling of 19993709 in words is "nineteen million, nine hundred ninety-three thousand, seven hundred nine".