1668967609 has 3 divisors (see below), whose sum is σ = 1669008463. Its totient is φ = 1668926756.

The previous prime is 1668967567. The next prime is 1668967637. The reversal of 1668967609 is 9067698661.

The square root of 1668967609 is 40853.

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.

It can be written as a sum of positive squares in only one way, i.e., 1660970025 + 7997584 = 40755^2 + 2828^2 .

It is not a de Polignac number, because 1668967609 - 2⁷ = 1668967481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1668967679) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 20427 + ... + 61279.

Almost surely, 2^1668967609 is an apocalyptic number.

1668967609 is the 40853-rd square number.

1668967609 is the 20427-th centered octagonal number.

It is an amenable number.

1668967609 is a deficient number, since it is larger than the sum of its proper divisors (40854).

1668967609 is an frugal number, since it uses more digits than its factorization.

1668967609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81706 (or 40853 counting only the distinct ones).

The product of its (nonzero) digits is 5878656, while the sum is 58.

The cubic root of 1668967609 is about 1186.1764643626.

The spelling of 1668967609 in words is "one billion, six hundred sixty-eight million, nine hundred sixty-seven thousand, six hundred nine".