21208814149 has 2 divisors, whose sum is σ = 21208814150. Its totient is φ = 21208814148.

The previous prime is 21208814113. The next prime is 21208814171. The reversal of 21208814149 is 94141880212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11461201249 + 9747612900 = 107057^2 + 98730^2 .

It is a cyclic number.

It is not a de Polignac number, because 21208814149 - 2¹¹ = 21208812101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21208815149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10604407074 + 10604407075.

It is an arithmetic number, because the mean of its divisors is an integer number (10604407075).

Almost surely, 2^21208814149 is an apocalyptic number.

It is an amenable number.

21208814149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21208814149 is an equidigital number, since it uses as much as digits as its factorization.

21208814149 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36864, while the sum is 40.

The spelling of 21208814149 in words is "twenty-one billion, two hundred eight million, eight hundred fourteen thousand, one hundred forty-nine".