1641343661 has 2 divisors, whose sum is σ = 1641343662. Its totient is φ = 1641343660.

The previous prime is 1641343651. The next prime is 1641343663. The reversal of 1641343661 is 1663431461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 965655625 + 675688036 = 31075^2 + 25994^2 .

It is a cyclic number.

It is not a de Polignac number, because 1641343661 - 2¹⁴ = 1641327277 is a prime.

Together with 1641343663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1641343663) 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, 820671830 + 820671831.

It is an arithmetic number, because the mean of its divisors is an integer number (820671831).

Almost surely, 2^1641343661 is an apocalyptic number.

It is an amenable number.

1641343661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1641343661 is an equidigital number, since it uses as much as digits as its factorization.

1641343661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 35.

The square root of 1641343661 is about 40513.4997377417. The cubic root of 1641343661 is about 1179.5956818853.

The spelling of 1641343661 in words is "one billion, six hundred forty-one million, three hundred forty-three thousand, six hundred sixty-one".