1644641 has 2 divisors, whose sum is σ = 1644642. Its totient is φ = 1644640.

The previous prime is 1644637. The next prime is 1644653. The reversal of 1644641 is 1464461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1638400 + 6241 = 1280^2 + 79^2 .

It is an emirp because it is prime and its reverse (1464461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1644641 - 2² = 1644637 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 1644641.

It is not a weakly prime, because it can be changed into another prime (1644611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822320 + 822321.

It is an arithmetic number, because the mean of its divisors is an integer number (822321).

2^1644641 is an apocalyptic number.

It is an amenable number.

1644641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1644641 is an equidigital number, since it uses as much as digits as its factorization.

1644641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 26.

The square root of 1644641 is about 1282.4355734305. The cubic root of 1644641 is about 118.0385060582.

The spelling of 1644641 in words is "one million, six hundred forty-four thousand, six hundred forty-one".