21213403601209 has 2 divisors, whose sum is σ = 21213403601210. Its totient is φ = 21213403601208.

The previous prime is 21213403601197. The next prime is 21213403601231. The reversal of 21213403601209 is 90210630431212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18279216176400 + 2934187424809 = 4275420^2 + 1712947^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213403601209 - 2¹¹ = 21213403599161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21213403601009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606701800604 + 10606701800605.

It is an arithmetic number, because the mean of its divisors is an integer number (10606701800605).

Almost surely, 2^{21213403601209} is an apocalyptic number.

It is an amenable number.

21213403601209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213403601209 is an equidigital number, since it uses as much as digits as its factorization.

21213403601209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 34.

The spelling of 21213403601209 in words is "twenty-one trillion, two hundred thirteen billion, four hundred three million, six hundred one thousand, two hundred nine".