21333210209 has 2 divisors, whose sum is σ = 21333210210. Its totient is φ = 21333210208.

The previous prime is 21333210193. The next prime is 21333210221. The reversal of 21333210209 is 90201233312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16711249984 + 4621960225 = 129272^2 + 67985^2 .

It is a cyclic number.

It is not a de Polignac number, because 21333210209 - 2⁴ = 21333210193 is a prime.

It is not a weakly prime, because it can be changed into another prime (21333210259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10666605104 + 10666605105.

It is an arithmetic number, because the mean of its divisors is an integer number (10666605105).

Almost surely, 2^21333210209 is an apocalyptic number.

It is an amenable number.

21333210209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21333210209 is an equidigital number, since it uses as much as digits as its factorization.

21333210209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 26.

The spelling of 21333210209 in words is "twenty-one billion, three hundred thirty-three million, two hundred ten thousand, two hundred nine".