669556213 has 2 divisors, whose sum is σ = 669556214. Its totient is φ = 669556212.

The previous prime is 669556211. The next prime is 669556229. The reversal of 669556213 is 312655966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 381303729 + 288252484 = 19527^2 + 16978^2 .

It is a cyclic number.

It is not a de Polignac number, because 669556213 - 2¹ = 669556211 is a prime.

Together with 669556211, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 669556213.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669556211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334778106 + 334778107.

It is an arithmetic number, because the mean of its divisors is an integer number (334778107).

Almost surely, 2^669556213 is an apocalyptic number.

It is an amenable number.

669556213 is a deficient number, since it is larger than the sum of its proper divisors (1).

669556213 is an equidigital number, since it uses as much as digits as its factorization.

669556213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 291600, while the sum is 43.

The square root of 669556213 is about 25875.7842972923. The cubic root of 669556213 is about 874.8407712437.

The spelling of 669556213 in words is "six hundred sixty-nine million, five hundred fifty-six thousand, two hundred thirteen".