666218071 has 8 divisors (see below), whose sum is σ = 701532800. Its totient is φ = 630928440.

The previous prime is 666218057. The next prime is 666218093. The reversal of 666218071 is 170812666.

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

It is not a de Polignac number, because 666218071 - 2²⁵ = 632663639 is a prime.

It is a super-2 number, since 2×666218071² = 887693036253922082, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 666218071.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666218011) 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, 76006 + ... + 84316.

It is an arithmetic number, because the mean of its divisors is an integer number (87691600).

Almost surely, 2^666218071 is an apocalyptic number.

666218071 is a deficient number, since it is larger than the sum of its proper divisors (35314729).

666218071 is a wasteful number, since it uses less digits than its factorization.

666218071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12549.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 666218071 is about 25811.2004951339. The cubic root of 666218071 is about 873.3844785650.

The spelling of 666218071 in words is "six hundred sixty-six million, two hundred eighteen thousand, seventy-one".