665143217 has 16 divisors (see below), whose sum is σ = 698107200. Its totient is φ = 632923200.

The previous prime is 665143211. The next prime is 665143229. The reversal of 665143217 is 712341566.

It is a cyclic number.

It is not a de Polignac number, because 665143217 - 2⁶ = 665143153 is a prime.

It is a super-2 number, since 2×665143217² = 884830998242218178, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665143211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 632342 + ... + 633392.

It is an arithmetic number, because the mean of its divisors is an integer number (43631700).

Almost surely, 2^665143217 is an apocalyptic number.

It is an amenable number.

665143217 is a deficient number, since it is larger than the sum of its proper divisors (32963983).

665143217 is a wasteful number, since it uses less digits than its factorization.

665143217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1376.

The product of its digits is 30240, while the sum is 35.

The square root of 665143217 is about 25790.3706254873. The cubic root of 665143217 is about 872.9145292849.

The spelling of 665143217 in words is "six hundred sixty-five million, one hundred forty-three thousand, two hundred seventeen".