21202331209 has 4 divisors (see below), whose sum is σ = 21202804116. Its totient is φ = 21201858304.

The previous prime is 21202331207. The next prime is 21202331219. The reversal of 21202331209 is 90213320212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4960103184 + 16242228025 = 70428^2 + 127445^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202331209 - 2¹ = 21202331207 is a prime.

It is a super-2 number, since 2×21202331209² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21202331207) 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 in 3 ways as a sum of consecutive naturals, for example, 161224 + ... + 261529.

It is an arithmetic number, because the mean of its divisors is an integer number (5300701029).

Almost surely, 2^21202331209 is an apocalyptic number.

It is an amenable number.

21202331209 is a deficient number, since it is larger than the sum of its proper divisors (472907).

21202331209 is an equidigital number, since it uses as much as digits as its factorization.

21202331209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 472906.

The product of its (nonzero) digits is 1296, while the sum is 25.

The spelling of 21202331209 in words is "twenty-one billion, two hundred two million, three hundred thirty-one thousand, two hundred nine".