21291202213 has 2 divisors, whose sum is σ = 21291202214. Its totient is φ = 21291202212.

The previous prime is 21291202211. The next prime is 21291202217. The reversal of 21291202213 is 31220219212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21199942404 + 91259809 = 145602^2 + 9553^2 .

It is a cyclic number.

It is not a de Polignac number, because 21291202213 - 2¹ = 21291202211 is a prime.

Together with 21291202211, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21291202211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10645601106 + 10645601107.

It is an arithmetic number, because the mean of its divisors is an integer number (10645601107).

Almost surely, 2^21291202213 is an apocalyptic number.

It is an amenable number.

21291202213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21291202213 is an equidigital number, since it uses as much as digits as its factorization.

21291202213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The spelling of 21291202213 in words is "twenty-one billion, two hundred ninety-one million, two hundred two thousand, two hundred thirteen".