666737213 has 8 divisors (see below), whose sum is σ = 670300920. Its totient is φ = 663182080.

The previous prime is 666737209. The next prime is 666737237. The reversal of 666737213 is 312737666.

It can be written as a sum of positive squares in 4 ways, for example, as 994009 + 665743204 = 997^2 + 25802^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 666737213 - 2² = 666737209 is a prime.

It is a super-2 number, since 2×666737213² = 889077022398014738, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666737273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 203081 + ... + 206337.

It is an arithmetic number, because the mean of its divisors is an integer number (83787615).

Almost surely, 2^666737213 is an apocalyptic number.

It is an amenable number.

666737213 is a deficient number, since it is larger than the sum of its proper divisors (3563707).

666737213 is a wasteful number, since it uses less digits than its factorization.

666737213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4287.

The product of its digits is 190512, while the sum is 41.

The square root of 666737213 is about 25821.2550624481. The cubic root of 666737213 is about 873.6112775988.

The spelling of 666737213 in words is "six hundred sixty-six million, seven hundred thirty-seven thousand, two hundred thirteen".