21001283309 has 2 divisors, whose sum is σ = 21001283310. Its totient is φ = 21001283308.

The previous prime is 21001283267. The next prime is 21001283341. The reversal of 21001283309 is 90338210012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15511955209 + 5489328100 = 124547^2 + 74090^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001283309 - 2¹⁶ = 21001217773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001283609) 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, 10500641654 + 10500641655.

It is an arithmetic number, because the mean of its divisors is an integer number (10500641655).

Almost surely, 2^21001283309 is an apocalyptic number.

It is an amenable number.

21001283309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001283309 is an equidigital number, since it uses as much as digits as its factorization.

21001283309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 29.

The spelling of 21001283309 in words is "twenty-one billion, one million, two hundred eighty-three thousand, three hundred nine".