21101301209 has 2 divisors, whose sum is σ = 21101301210. Its totient is φ = 21101301208.

The previous prime is 21101301197. The next prime is 21101301211. The reversal of 21101301209 is 90210310112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10708110400 + 10393190809 = 103480^2 + 101947^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101301209 - 2²⁰ = 21100252633 is a prime.

Together with 21101301211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21101301229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550650604 + 10550650605.

It is an arithmetic number, because the mean of its divisors is an integer number (10550650605).

Almost surely, 2^21101301209 is an apocalyptic number.

It is an amenable number.

21101301209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101301209 is an equidigital number, since it uses as much as digits as its factorization.

21101301209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 20.

The spelling of 21101301209 in words is "twenty-one billion, one hundred one million, three hundred one thousand, two hundred nine".