1668866 has 4 divisors (see below), whose sum is σ = 2503302. Its totient is φ = 834432.

The previous prime is 1668847. The next prime is 1668869. The reversal of 1668866 is 6688661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1525225 + 143641 = 1235^2 + 379^2 .

It is a super-2 number, since 2×1668866² = 5570227451912, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 417215 + ... + 417218.

2^1668866 is an apocalyptic number.

1668866 is a deficient number, since it is larger than the sum of its proper divisors (834436).

1668866 is an equidigital number, since it uses as much as digits as its factorization.

1668866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834435.

The product of its digits is 82944, while the sum is 41.

The square root of 1668866 is about 1291.8459660501. The cubic root of 1668866 is about 118.6152391866.

The spelling of 1668866 in words is "one million, six hundred sixty-eight thousand, eight hundred sixty-six".