1669598921 has 2 divisors, whose sum is σ = 1669598922. Its totient is φ = 1669598920.

The previous prime is 1669598897. The next prime is 1669598923. The reversal of 1669598921 is 1298959661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1663742521 + 5856400 = 40789^2 + 2420^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1669598921 is a prime.

Together with 1669598923, 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 (1669598923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834799460 + 834799461.

It is an arithmetic number, because the mean of its divisors is an integer number (834799461).

Almost surely, 2^1669598921 is an apocalyptic number.

It is an amenable number.

1669598921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1669598921 is an equidigital number, since it uses as much as digits as its factorization.

1669598921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2099520, while the sum is 56.

The square root of 1669598921 is about 40860.7258990831. The cubic root of 1669598921 is about 1186.3260085141.

The spelling of 1669598921 in words is "one billion, six hundred sixty-nine million, five hundred ninety-eight thousand, nine hundred twenty-one".