666889249 has 8 divisors (see below), whose sum is σ = 742953960. Its totient is φ = 594362496.

The previous prime is 666889247. The next prime is 666889261. The reversal of 666889249 is 942988666.

It can be written as a sum of positive squares in 4 ways, for example, as 12552849 + 654336400 = 3543^2 + 25580^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 666889249 - 2¹ = 666889247 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666889193 and 666889202.

It is not an unprimeable number, because it can be changed into a prime (666889247) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 884092 + ... + 884845.

It is an arithmetic number, because the mean of its divisors is an integer number (92869245).

Almost surely, 2^666889249 is an apocalyptic number.

It is an amenable number.

666889249 is a deficient number, since it is larger than the sum of its proper divisors (76064711).

666889249 is a wasteful number, since it uses less digits than its factorization.

666889249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1768979.

The product of its digits is 8957952, while the sum is 58.

The square root of 666889249 is about 25824.1989033542. The cubic root of 666889249 is about 873.6776757075.

The spelling of 666889249 in words is "six hundred sixty-six million, eight hundred eighty-nine thousand, two hundred forty-nine".