666838871 has 2 divisors, whose sum is σ = 666838872. Its totient is φ = 666838870.

The previous prime is 666838859. The next prime is 666838927. The reversal of 666838871 is 178838666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666838871 - 2¹⁸ = 666576727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666838771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333419435 + 333419436.

It is an arithmetic number, because the mean of its divisors is an integer number (333419436).

Almost surely, 2^666838871 is an apocalyptic number.

666838871 is a deficient number, since it is larger than the sum of its proper divisors (1).

666838871 is an equidigital number, since it uses as much as digits as its factorization.

666838871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2322432, while the sum is 53.

The square root of 666838871 is about 25823.2234819745. The cubic root of 666838871 is about 873.6556754316.

The spelling of 666838871 in words is "six hundred sixty-six million, eight hundred thirty-eight thousand, eight hundred seventy-one".