665530213 has 4 divisors (see below), whose sum is σ = 666585568. Its totient is φ = 664474860.

The previous prime is 665530181. The next prime is 665530241. The reversal of 665530213 is 312035566.

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.

It is a cyclic number.

It is not a de Polignac number, because 665530213 - 2⁵ = 665530181 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665530253) 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, 526731 + ... + 527992.

It is an arithmetic number, because the mean of its divisors is an integer number (166646392).

Almost surely, 2^665530213 is an apocalyptic number.

It is an amenable number.

665530213 is a deficient number, since it is larger than the sum of its proper divisors (1055355).

665530213 is a wasteful number, since it uses less digits than its factorization.

665530213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055354.

The product of its (nonzero) digits is 16200, while the sum is 31.

The square root of 665530213 is about 25797.8722572231. The cubic root of 665530213 is about 873.0837905446.

Adding to 665530213 its reverse (312035566), we get a palindrome (977565779).

The spelling of 665530213 in words is "six hundred sixty-five million, five hundred thirty thousand, two hundred thirteen".