21403301209 has 2 divisors, whose sum is σ = 21403301210. Its totient is φ = 21403301208.

The previous prime is 21403301207. The next prime is 21403301221. The reversal of 21403301209 is 90210330412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21358945609 + 44355600 = 146147^2 + 6660^2 .

It is a cyclic number.

It is not a de Polignac number, because 21403301209 - 2¹ = 21403301207 is a prime.

Together with 21403301207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21403301207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701650604 + 10701650605.

It is an arithmetic number, because the mean of its divisors is an integer number (10701650605).

Almost surely, 2^21403301209 is an apocalyptic number.

It is an amenable number.

21403301209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403301209 is an equidigital number, since it uses as much as digits as its factorization.

21403301209 is an evil number, because the sum of its binary digits is even.

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

The spelling of 21403301209 in words is "twenty-one billion, four hundred three million, three hundred one thousand, two hundred nine".