21041320009 has 2 divisors, whose sum is σ = 21041320010. Its totient is φ = 21041320008.

The previous prime is 21041319991. The next prime is 21041320021. The reversal of 21041320009 is 90002314012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16603095609 + 4438224400 = 128853^2 + 66620^2 .

It is a cyclic number.

It is not a de Polignac number, because 21041320009 - 2¹³ = 21041311817 is a prime.

It is a super-2 number, since 2×21041320009² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21041320609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10520660004 + 10520660005.

It is an arithmetic number, because the mean of its divisors is an integer number (10520660005).

Almost surely, 2^21041320009 is an apocalyptic number.

It is an amenable number.

21041320009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21041320009 is an equidigital number, since it uses as much as digits as its factorization.

21041320009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 22.

The spelling of 21041320009 in words is "twenty-one billion, forty-one million, three hundred twenty thousand, nine".