666921139 has 2 divisors, whose sum is σ = 666921140. Its totient is φ = 666921138.

The previous prime is 666921119. The next prime is 666921163. The reversal of 666921139 is 931129666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666921139 - 2¹¹ = 666919091 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 666921095 and 666921104.

It is not a weakly prime, because it can be changed into another prime (666921119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333460569 + 333460570.

It is an arithmetic number, because the mean of its divisors is an integer number (333460570).

Almost surely, 2^666921139 is an apocalyptic number.

666921139 is a deficient number, since it is larger than the sum of its proper divisors (1).

666921139 is an equidigital number, since it uses as much as digits as its factorization.

666921139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 104976, while the sum is 43.

The square root of 666921139 is about 25824.8163401020. The cubic root of 666921139 is about 873.6916016265.

The spelling of 666921139 in words is "six hundred sixty-six million, nine hundred twenty-one thousand, one hundred thirty-nine".