1668749 has 4 divisors (see below), whose sum is σ = 1673664. Its totient is φ = 1663836.

The previous prime is 1668743. The next prime is 1668757. The reversal of 1668749 is 9478661.

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: 9478661 = 1249 ⋅7589.

It is a cyclic number.

It is not a de Polignac number, because 1668749 - 2¹² = 1664653 is a prime.

It is a d-powerful number, because it can be written as 1 + 6² + 6⁷ + 8⁵ + 7⁷ + 4⁵ + 9⁶ .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668743) 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, 1907 + ... + 2640.

It is an arithmetic number, because the mean of its divisors is an integer number (418416).

2^1668749 is an apocalyptic number.

It is an amenable number.

1668749 is a deficient number, since it is larger than the sum of its proper divisors (4915).

1668749 is an equidigital number, since it uses as much as digits as its factorization.

1668749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4914.

The product of its digits is 72576, while the sum is 41.

The square root of 1668749 is about 1291.8006812198. The cubic root of 1668749 is about 118.6124671831.

The spelling of 1668749 in words is "one million, six hundred sixty-eight thousand, seven hundred forty-nine".