669547219021 has 2 divisors, whose sum is σ = 669547219022. Its totient is φ = 669547219020.

The previous prime is 669547219009. The next prime is 669547219039. The reversal of 669547219021 is 120912745966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 667956405796 + 1590813225 = 817286^2 + 39885^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-669547219021 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 669547219021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669547219001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334773609510 + 334773609511.

It is an arithmetic number, because the mean of its divisors is an integer number (334773609511).

Almost surely, 2^669547219021 is an apocalyptic number.

It is an amenable number.

669547219021 is a deficient number, since it is larger than the sum of its proper divisors (1).

669547219021 is an equidigital number, since it uses as much as digits as its factorization.

669547219021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1632960, while the sum is 52.

The spelling of 669547219021 in words is "six hundred sixty-nine billion, five hundred forty-seven million, two hundred nineteen thousand, twenty-one".