21418209149 has 2 divisors, whose sum is σ = 21418209150. Its totient is φ = 21418209148.

The previous prime is 21418209133. The next prime is 21418209151. The reversal of 21418209149 is 94190281412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12369443524 + 9048765625 = 111218^2 + 95125^2 .

It is a cyclic number.

It is not a de Polignac number, because 21418209149 - 2⁴ = 21418209133 is a prime.

It is a Sophie Germain prime.

Together with 21418209151, it forms a pair of twin primes.

It is a Chen 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 (21418209949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10709104574 + 10709104575.

It is an arithmetic number, because the mean of its divisors is an integer number (10709104575).

Almost surely, 2^21418209149 is an apocalyptic number.

It is an amenable number.

21418209149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21418209149 is an equidigital number, since it uses as much as digits as its factorization.

21418209149 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 41.

The spelling of 21418209149 in words is "twenty-one billion, four hundred eighteen million, two hundred nine thousand, one hundred forty-nine".