21320000309 has 2 divisors, whose sum is σ = 21320000310. Its totient is φ = 21320000308.

The previous prime is 21320000279. The next prime is 21320000329. The reversal of 21320000309 is 90300002312.

It is an a-pointer prime, because the next prime (21320000329) can be obtained adding 21320000309 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20867247025 + 452753284 = 144455^2 + 21278^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21320000309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21320000329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660000154 + 10660000155.

It is an arithmetic number, because the mean of its divisors is an integer number (10660000155).

Almost surely, 2^21320000309 is an apocalyptic number.

It is an amenable number.

21320000309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320000309 is an equidigital number, since it uses as much as digits as its factorization.

21320000309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 20.

The spelling of 21320000309 in words is "twenty-one billion, three hundred twenty million, three hundred nine", and thus it is an aban number.