666811271 has 32 divisors (see below), whose sum is σ = 806830080. Its totient is φ = 539136000.

The previous prime is 666811261. The next prime is 666811291. The reversal of 666811271 is 172118666.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666811271 is a prime.

It is a super-2 number, since 2×666811271² = 889274542265270882, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666811261) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1662671 + ... + 1663071.

It is an arithmetic number, because the mean of its divisors is an integer number (25213440).

Almost surely, 2^666811271 is an apocalyptic number.

666811271 is a deficient number, since it is larger than the sum of its proper divisors (140018809).

666811271 is a wasteful number, since it uses less digits than its factorization.

666811271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 615.

The product of its digits is 24192, while the sum is 38.

The square root of 666811271 is about 25822.6890737584. The cubic root of 666811271 is about 873.6436219305.

The spelling of 666811271 in words is "six hundred sixty-six million, eight hundred eleven thousand, two hundred seventy-one".