20467218509 has 2 divisors, whose sum is σ = 20467218510. Its totient is φ = 20467218508.

The previous prime is 20467218367. The next prime is 20467218511. The reversal of 20467218509 is 90581276402.

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., 19050072484 + 1417146025 = 138022^2 + 37645^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20467218509 is a prime.

Together with 20467218511, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20467218509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20467218529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10233609254 + 10233609255.

It is an arithmetic number, because the mean of its divisors is an integer number (10233609255).

Almost surely, 2^20467218509 is an apocalyptic number.

It is an amenable number.

20467218509 is a deficient number, since it is larger than the sum of its proper divisors (1).

20467218509 is an equidigital number, since it uses as much as digits as its factorization.

20467218509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 241920, while the sum is 44.

The spelling of 20467218509 in words is "twenty billion, four hundred sixty-seven million, two hundred eighteen thousand, five hundred nine".