213365561 has 2 divisors, whose sum is σ = 213365562. Its totient is φ = 213365560.

The previous prime is 213365543. The next prime is 213365563. The reversal of 213365561 is 165563312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213306025 + 59536 = 14605^2 + 244^2 .

It is a cyclic number.

It is not a de Polignac number, because 213365561 - 2¹⁴ = 213349177 is a prime.

It is a super-3 number, since 3×213365561³ (a number of 26 digits) contains 333 as substring.

Together with 213365563, 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 (213365563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106682780 + 106682781.

It is an arithmetic number, because the mean of its divisors is an integer number (106682781).

Almost surely, 2^213365561 is an apocalyptic number.

It is an amenable number.

213365561 is a deficient number, since it is larger than the sum of its proper divisors (1).

213365561 is an equidigital number, since it uses as much as digits as its factorization.

213365561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 32.

The square root of 213365561 is about 14607.0380638924. The cubic root of 213365561 is about 597.5507199464.

The spelling of 213365561 in words is "two hundred thirteen million, three hundred sixty-five thousand, five hundred sixty-one".