1663213 has 4 divisors (see below), whose sum is σ = 1665820. Its totient is φ = 1660608.

The previous prime is 1663183. The next prime is 1663217. The reversal of 1663213 is 3123661.

It is the 527-th star number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 3123661 = 53 ⋅58937.

It can be written as a sum of positive squares in 2 ways, for example, as 191844 + 1471369 = 438^2 + 1213^2 .

It is a 3-Lehmer number, since φ(1663213) divides (1663213-1)³.

It is a cyclic number.

It is not a de Polignac number, because 1663213 - 2⁹ = 1662701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663217) 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 in 3 ways as a sum of consecutive naturals, for example, 373 + ... + 1861.

It is an arithmetic number, because the mean of its divisors is an integer number (416455).

2^1663213 is an apocalyptic number.

It is an amenable number.

1663213 is a deficient number, since it is larger than the sum of its proper divisors (2607).

1663213 is a wasteful number, since it uses less digits than its factorization.

1663213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2606.

The product of its digits is 648, while the sum is 22.

The square root of 1663213 is about 1289.6561557252. The cubic root of 1663213 is about 118.4811580242.

Adding to 1663213 its reverse (3123661), we get a palindrome (4786874).

The spelling of 1663213 in words is "one million, six hundred sixty-three thousand, two hundred thirteen".