1668787 has 6 divisors (see below), whose sum is σ = 1716308. Its totient is φ = 1621704.

The previous prime is 1668773. The next prime is 1668791. The reversal of 1668787 is 7878661.

It is not a de Polignac number, because 1668787 - 2¹⁹ = 1144499 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1668727) 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 5 ways as a sum of consecutive naturals, for example, 8373 + ... + 8569.

2^1668787 is an apocalyptic number.

1668787 is a deficient number, since it is larger than the sum of its proper divisors (47521).

1668787 is an frugal number, since it uses more digits than its factorization.

1668787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437 (or 240 counting only the distinct ones).

The product of its digits is 112896, while the sum is 43.

The square root of 1668787 is about 1291.8153892875. The cubic root of 1668787 is about 118.6133675061.

Multiplying 1668787 by its sum of digits (43), we get a square (71757841 = 8471²).

1668787 divided by its sum of digits (43) gives a square (38809 = 197²).

The spelling of 1668787 in words is "one million, six hundred sixty-eight thousand, seven hundred eighty-seven".