666656471 has 16 divisors (see below), whose sum is σ = 726463584. Its totient is φ = 608114304.

The previous prime is 666656467. The next prime is 666656489. The reversal of 666656471 is 174656666.

It is a cyclic number.

It is not a de Polignac number, because 666656471 - 2² = 666656467 is a prime.

It is a super-3 number, since 3×666656471³ (a number of 27 digits) contains 333 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 (666656461) 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, 416645 + ... + 418241.

It is an arithmetic number, because the mean of its divisors is an integer number (45403974).

Almost surely, 2^666656471 is an apocalyptic number.

666656471 is a deficient number, since it is larger than the sum of its proper divisors (59807113).

666656471 is a wasteful number, since it uses less digits than its factorization.

666656471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1970.

The product of its digits is 1088640, while the sum is 47.

The square root of 666656471 is about 25819.6915357252. The cubic root of 666656471 is about 873.5760113460.

The spelling of 666656471 in words is "six hundred sixty-six million, six hundred fifty-six thousand, four hundred seventy-one".