666987019 has 2 divisors, whose sum is σ = 666987020. Its totient is φ = 666987018.

The previous prime is 666986987. The next prime is 666987029. The reversal of 666987019 is 910789666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666987019 - 2⁵ = 666986987 is a prime.

It is a super-2 number, since 2×666987019² = 889743367029012722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (666987029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333493509 + 333493510.

It is an arithmetic number, because the mean of its divisors is an integer number (333493510).

Almost surely, 2^666987019 is an apocalyptic number.

666987019 is a deficient number, since it is larger than the sum of its proper divisors (1).

666987019 is an equidigital number, since it uses as much as digits as its factorization.

666987019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 979776, while the sum is 52.

The square root of 666987019 is about 25826.0918259035. The cubic root of 666987019 is about 873.7203690995.

The spelling of 666987019 in words is "six hundred sixty-six million, nine hundred eighty-seven thousand, nineteen".