1668551 has 2 divisors, whose sum is σ = 1668552. Its totient is φ = 1668550.

The previous prime is 1668539. The next prime is 1668553. The reversal of 1668551 is 1558661.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668551 is a prime.

Together with 1668553, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668553) 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 as a sum of consecutive naturals, namely, 834275 + 834276.

It is an arithmetic number, because the mean of its divisors is an integer number (834276).

2^1668551 is an apocalyptic number.

1668551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668551 is an equidigital number, since it uses as much as digits as its factorization.

1668551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7200, while the sum is 32.

The square root of 1668551 is about 1291.7240417365. The cubic root of 1668551 is about 118.6077758050.

The spelling of 1668551 in words is "one million, six hundred sixty-eight thousand, five hundred fifty-one".