1668557 has 4 divisors (see below), whose sum is σ = 1820256. Its totient is φ = 1516860.

The previous prime is 1668553. The next prime is 1668587. The reversal of 1668557 is 7558661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7558661 = 11 ⋅687151.

It is a cyclic number.

It is not a de Polignac number, because 1668557 - 2² = 1668553 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1668557.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75833 + ... + 75854.

It is an arithmetic number, because the mean of its divisors is an integer number (455064).

2^1668557 is an apocalyptic number.

It is an amenable number.

1668557 is a deficient number, since it is larger than the sum of its proper divisors (151699).

1668557 is a wasteful number, since it uses less digits than its factorization.

1668557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151698.

The product of its digits is 50400, while the sum is 38.

The square root of 1668557 is about 1291.7263642119. The cubic root of 1668557 is about 118.6079179734.

The spelling of 1668557 in words is "one million, six hundred sixty-eight thousand, five hundred fifty-seven".