1668477409 has 3 divisors (see below), whose sum is σ = 1668518257. Its totient is φ = 1668436562.

The previous prime is 1668477401. The next prime is 1668477413. The reversal of 1668477409 is 9047748661.

The square root of 1668477409 is 40847.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9047748661 = 7 ⋅1292535523.

It is not a de Polignac number, because 1668477409 - 2³ = 1668477401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1668477401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 20424 + ... + 61270.

Almost surely, 2^1668477409 is an apocalyptic number.

1668477409 is the 40847-th square number.

1668477409 is the 20424-th centered octagonal number.

It is an amenable number.

1668477409 is a deficient number, since it is larger than the sum of its proper divisors (40848).

1668477409 is an frugal number, since it uses more digits than its factorization.

1668477409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81694 (or 40847 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 52.

The cubic root of 1668477409 is about 1186.0603205786.

The spelling of 1668477409 in words is "one billion, six hundred sixty-eight million, four hundred seventy-seven thousand, four hundred nine".