18940709 has 2 divisors, whose sum is σ = 18940710. Its totient is φ = 18940708.

The previous prime is 18940693. The next prime is 18940717. The reversal of 18940709 is 90704981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17724100 + 1216609 = 4210^2 + 1103^2 .

It is an emirp because it is prime and its reverse (90704981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18940709 - 2⁴ = 18940693 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18940759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9470354 + 9470355.

It is an arithmetic number, because the mean of its divisors is an integer number (9470355).

Almost surely, 2^18940709 is an apocalyptic number.

It is an amenable number.

18940709 is a deficient number, since it is larger than the sum of its proper divisors (1).

18940709 is an equidigital number, since it uses as much as digits as its factorization.

18940709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 18940709 is about 4352.0924852305. The cubic root of 18940709 is about 266.5623103822.

The spelling of 18940709 in words is "eighteen million, nine hundred forty thousand, seven hundred nine".