1668644 has 6 divisors (see below), whose sum is σ = 2920134. Its totient is φ = 834320.

The previous prime is 1668629. The next prime is 1668647. The reversal of 1668644 is 4468661.

It can be written as a sum of positive squares in only one way, i.e., 1537600 + 131044 = 1240^2 + 362^2 .

It is not an unprimeable number, because it can be changed into a prime (1668647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 208577 + ... + 208584.

It is an arithmetic number, because the mean of its divisors is an integer number (486689).

2^1668644 is an apocalyptic number.

It is an amenable number.

1668644 is a deficient number, since it is larger than the sum of its proper divisors (1251490).

1668644 is a wasteful number, since it uses less digits than its factorization.

1668644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 417165 (or 417163 counting only the distinct ones).

The product of its digits is 27648, while the sum is 35.

The square root of 1668644 is about 1291.7600396358. The cubic root of 1668644 is about 118.6099793773.

It can be divided in two parts, 16 and 68644, that multiplied together give a square (1098304 = 1048²).

The spelling of 1668644 in words is "one million, six hundred sixty-eight thousand, six hundred forty-four".