1668491 has 4 divisors (see below), whose sum is σ = 1820184. Its totient is φ = 1516800.

The previous prime is 1668481. The next prime is 1668503. The reversal of 1668491 is 1948661.

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

It is a cyclic number.

It is not a de Polignac number, because 1668491 - 2⁶ = 1668427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1668481) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75830 + ... + 75851.

It is an arithmetic number, because the mean of its divisors is an integer number (455046).

2^1668491 is an apocalyptic number.

1668491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1668491 is a deficient number, since it is larger than the sum of its proper divisors (151693).

1668491 is a wasteful number, since it uses less digits than its factorization.

1668491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151692.

The product of its digits is 10368, while the sum is 35.

The square root of 1668491 is about 1291.7008167529. The cubic root of 1668491 is about 118.6063541020.

The spelling of 1668491 in words is "one million, six hundred sixty-eight thousand, four hundred ninety-one".