666478366 has 4 divisors (see below), whose sum is σ = 999717552. Its totient is φ = 333239182.

The previous prime is 666478361. The next prime is 666478399. The reversal of 666478366 is 663874666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666478361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166619590 + ... + 166619593.

It is an arithmetic number, because the mean of its divisors is an integer number (249929388).

Almost surely, 2^666478366 is an apocalyptic number.

666478366 is a deficient number, since it is larger than the sum of its proper divisors (333239186).

666478366 is a wasteful number, since it uses less digits than its factorization.

666478366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333239185.

The product of its digits is 5225472, while the sum is 52.

The square root of 666478366 is about 25816.2422904651. The cubic root of 666478366 is about 873.4982090995.

The spelling of 666478366 in words is "six hundred sixty-six million, four hundred seventy-eight thousand, three hundred sixty-six".