1668642 has 16 divisors (see below), whose sum is σ = 3385152. Its totient is φ = 548240.

The previous prime is 1668629. The next prime is 1668647. The reversal of 1668642 is 2468661.

It is a happy number.

It is a super-2 number, since 2×1668642² = 5568732248328, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a nialpdrome in base 6.

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 in 7 ways as a sum of consecutive naturals, for example, 1533 + ... + 2384.

It is an arithmetic number, because the mean of its divisors is an integer number (211572).

2^1668642 is an apocalyptic number.

1668642 is an abundant number, since it is smaller than the sum of its proper divisors (1716510).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1668642 is a wasteful number, since it uses less digits than its factorization.

1668642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3993.

The product of its digits is 13824, while the sum is 33.

The square root of 1668642 is about 1291.7592654980. The cubic root of 1668642 is about 118.6099319895.

The spelling of 1668642 in words is "one million, six hundred sixty-eight thousand, six hundred forty-two".