1640641 has 2 divisors, whose sum is σ = 1640642. Its totient is φ = 1640640.

The previous prime is 1640633. The next prime is 1640657. The reversal of 1640641 is 1460461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1537600 + 103041 = 1240^2 + 321^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640641 - 2³ = 1640633 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1640621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820320 + 820321.

It is an arithmetic number, because the mean of its divisors is an integer number (820321).

2^1640641 is an apocalyptic number.

It is an amenable number.

1640641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640641 is an equidigital number, since it uses as much as digits as its factorization.

1640641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 1640641 is about 1280.8750914902. The cubic root of 1640641 is about 117.9427329129.

The spelling of 1640641 in words is "one million, six hundred forty thousand, six hundred forty-one".