666689371 has 4 divisors (see below), whose sum is σ = 667301544. Its totient is φ = 666077200.

The previous prime is 666689351. The next prime is 666689377. The reversal of 666689371 is 173986666.

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

It is a cyclic number.

It is not a de Polignac number, because 666689371 - 2²³ = 658300763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666689377) 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, 304450 + ... + 306631.

It is an arithmetic number, because the mean of its divisors is an integer number (166825386).

Almost surely, 2^666689371 is an apocalyptic number.

666689371 is a deficient number, since it is larger than the sum of its proper divisors (612173).

666689371 is a wasteful number, since it uses less digits than its factorization.

666689371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 612172.

The product of its digits is 1959552, while the sum is 52.

The square root of 666689371 is about 25820.3286384972. The cubic root of 666689371 is about 873.5903816548.

The spelling of 666689371 in words is "six hundred sixty-six million, six hundred eighty-nine thousand, three hundred seventy-one".