21311411509 has 2 divisors, whose sum is σ = 21311411510. Its totient is φ = 21311411508.

The previous prime is 21311411501. The next prime is 21311411557. The reversal of 21311411509 is 90511411312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18829877284 + 2481534225 = 137222^2 + 49815^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311411509 - 2³ = 21311411501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21311411501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655705754 + 10655705755.

It is an arithmetic number, because the mean of its divisors is an integer number (10655705755).

Almost surely, 2^21311411509 is an apocalyptic number.

It is an amenable number.

21311411509 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311411509 is an equidigital number, since it uses as much as digits as its factorization.

21311411509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 28.

The spelling of 21311411509 in words is "twenty-one billion, three hundred eleven million, four hundred eleven thousand, five hundred nine".