1680884021 has 2 divisors, whose sum is σ = 1680884022. Its totient is φ = 1680884020.

The previous prime is 1680884017. The next prime is 1680884047. The reversal of 1680884021 is 1204880861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1680180100 + 703921 = 40990^2 + 839^2 .

It is a cyclic number.

It is not a de Polignac number, because 1680884021 - 2² = 1680884017 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 (1680884071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840442010 + 840442011.

It is an arithmetic number, because the mean of its divisors is an integer number (840442011).

Almost surely, 2^1680884021 is an apocalyptic number.

It is an amenable number.

1680884021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1680884021 is an equidigital number, since it uses as much as digits as its factorization.

1680884021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24576, while the sum is 38.

The square root of 1680884021 is about 40998.5855975545. The cubic root of 1680884021 is about 1188.9928679512.

The spelling of 1680884021 in words is "one billion, six hundred eighty million, eight hundred eighty-four thousand, twenty-one".