1646339021 has 2 divisors, whose sum is σ = 1646339022. Its totient is φ = 1646339020.

The previous prime is 1646338933. The next prime is 1646339033. The reversal of 1646339021 is 1209336461.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1622961796 + 23377225 = 40286^2 + 4835^2 .

It is a cyclic number.

It is not a de Polignac number, because 1646339021 - 2¹⁴ = 1646322637 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 (1646339521) 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, 823169510 + 823169511.

It is an arithmetic number, because the mean of its divisors is an integer number (823169511).

Almost surely, 2^1646339021 is an apocalyptic number.

It is an amenable number.

1646339021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1646339021 is an equidigital number, since it uses as much as digits as its factorization.

1646339021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 35.

The square root of 1646339021 is about 40575.1034625914. The cubic root of 1646339021 is about 1180.7911531017.

The spelling of 1646339021 in words is "one billion, six hundred forty-six million, three hundred thirty-nine thousand, twenty-one".