666539967 has 4 divisors (see below), whose sum is σ = 888719960. Its totient is φ = 444359976.

The previous prime is 666539963. The next prime is 666539981. The reversal of 666539967 is 769935666.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 666539967 - 2² = 666539963 is a prime.

It is a super-2 number, since 2×666539967² = 888551055216722178, which contains 22 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 (666539963) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111089992 + ... + 111089997.

It is an arithmetic number, because the mean of its divisors is an integer number (222179990).

Almost surely, 2^666539967 is an apocalyptic number.

666539967 is a deficient number, since it is larger than the sum of its proper divisors (222179993).

666539967 is a wasteful number, since it uses less digits than its factorization.

666539967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222179992.

The product of its digits is 11022480, while the sum is 57.

The square root of 666539967 is about 25817.4353296372. The cubic root of 666539967 is about 873.5251200532.

The spelling of 666539967 in words is "six hundred sixty-six million, five hundred thirty-nine thousand, nine hundred sixty-seven".