668142569 has 4 divisors (see below), whose sum is σ = 668495940. Its totient is φ = 667789200.

The previous prime is 668142533. The next prime is 668142593. The reversal of 668142569 is 965241866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 246866944 + 421275625 = 15712^2 + 20525^2 .

It is a cyclic number.

It is not a de Polignac number, because 668142569 - 2²⁰ = 667093993 is a prime.

It is a super-2 number, since 2×668142569² = 892828985019839522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668142509) 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 3 ways as a sum of consecutive naturals, for example, 173834 + ... + 177635.

It is an arithmetic number, because the mean of its divisors is an integer number (167123985).

Almost surely, 2^668142569 is an apocalyptic number.

It is an amenable number.

668142569 is a deficient number, since it is larger than the sum of its proper divisors (353371).

668142569 is a wasteful number, since it uses less digits than its factorization.

668142569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353370.

The product of its digits is 622080, while the sum is 47.

The square root of 668142569 is about 25848.4538996049. The cubic root of 668142569 is about 874.2246493163.

The spelling of 668142569 in words is "six hundred sixty-eight million, one hundred forty-two thousand, five hundred sixty-nine".