19717913 has 2 divisors, whose sum is σ = 19717914. Its totient is φ = 19717912.

The previous prime is 19717903. The next prime is 19717921. The reversal of 19717913 is 31971791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13778944 + 5938969 = 3712^2 + 2437^2 .

It is a cyclic number.

It is not a de Polignac number, because 19717913 - 2⁶ = 19717849 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19717903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9858956 + 9858957.

It is an arithmetic number, because the mean of its divisors is an integer number (9858957).

Almost surely, 2^19717913 is an apocalyptic number.

It is an amenable number.

19717913 is a deficient number, since it is larger than the sum of its proper divisors (1).

19717913 is an equidigital number, since it uses as much as digits as its factorization.

19717913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11907, while the sum is 38.

The square root of 19717913 is about 4440.4856716355. The cubic root of 19717913 is about 270.1595444803.

The spelling of 19717913 in words is "nineteen million, seven hundred seventeen thousand, nine hundred thirteen".