1669634364221 has 2 divisors, whose sum is σ = 1669634364222. Its totient is φ = 1669634364220.

The previous prime is 1669634364199. The next prime is 1669634364239. The reversal of 1669634364221 is 1224634369661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 928977907225 + 740656456996 = 963835^2 + 860614^2 .

It is an emirp because it is prime and its reverse (1224634369661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1669634364221 - 2¹⁴ = 1669634347837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1669634364241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834817182110 + 834817182111.

It is an arithmetic number, because the mean of its divisors is an integer number (834817182111).

Almost surely, 2^{1669634364221} is an apocalyptic number.

It is an amenable number.

1669634364221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1669634364221 is an equidigital number, since it uses as much as digits as its factorization.

1669634364221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6718464, while the sum is 53.

The spelling of 1669634364221 in words is "one trillion, six hundred sixty-nine billion, six hundred thirty-four million, three hundred sixty-four thousand, two hundred twenty-one".