1671330821 has 2 divisors, whose sum is σ = 1671330822. Its totient is φ = 1671330820.

The previous prime is 1671330799. The next prime is 1671330851. The reversal of 1671330821 is 1280331761.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1651528321 + 19802500 = 40639^2 + 4450^2 .

It is a cyclic number.

It is not a de Polignac number, because 1671330821 - 2⁶ = 1671330757 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1671330851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 835665410 + 835665411.

It is an arithmetic number, because the mean of its divisors is an integer number (835665411).

Almost surely, 2^1671330821 is an apocalyptic number.

It is an amenable number.

1671330821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1671330821 is an equidigital number, since it uses as much as digits as its factorization.

1671330821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 1671330821 is about 40881.9131279347. The cubic root of 1671330821 is about 1186.7360646810.

The spelling of 1671330821 in words is "one billion, six hundred seventy-one million, three hundred thirty thousand, eight hundred twenty-one".