1644493 has 2 divisors, whose sum is σ = 1644494. Its totient is φ = 1644492.

The previous prime is 1644491. The next prime is 1644497. The reversal of 1644493 is 3944461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1605289 + 39204 = 1267^2 + 198^2 .

It is an emirp because it is prime and its reverse (3944461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1644493 - 2¹ = 1644491 is a prime.

Together with 1644491, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1644491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822246 + 822247.

It is an arithmetic number, because the mean of its divisors is an integer number (822247).

2^1644493 is an apocalyptic number.

It is an amenable number.

1644493 is a deficient number, since it is larger than the sum of its proper divisors (1).

1644493 is an equidigital number, since it uses as much as digits as its factorization.

1644493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 31.

The square root of 1644493 is about 1282.3778694285. The cubic root of 1644493 is about 118.0349652200.

Subtracting 1644493 from its reverse (3944461), we obtain a cube (2299968 = 132³).

The spelling of 1644493 in words is "one million, six hundred forty-four thousand, four hundred ninety-three".