666698539 has 16 divisors (see below), whose sum is σ = 751464000. Its totient is φ = 586878336.

The previous prime is 666698533. The next prime is 666698573. The reversal of 666698539 is 935896666.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 666698539 - 2⁵ = 666698507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666698533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 101157 + ... + 107545.

It is an arithmetic number, because the mean of its divisors is an integer number (46966500).

Almost surely, 2^666698539 is an apocalyptic number.

666698539 is a deficient number, since it is larger than the sum of its proper divisors (84765461).

666698539 is a wasteful number, since it uses less digits than its factorization.

666698539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6774.

The product of its digits is 12597120, while the sum is 58.

The square root of 666698539 is about 25820.5061724204. The cubic root of 666698539 is about 873.5943860383.

The spelling of 666698539 in words is "six hundred sixty-six million, six hundred ninety-eight thousand, five hundred thirty-nine".