666478399 has 2 divisors, whose sum is σ = 666478400. Its totient is φ = 666478398.

The previous prime is 666478361. The next prime is 666478403. The reversal of 666478399 is 993874666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666478399 - 2¹¹ = 666476351 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666478499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333239199 + 333239200.

It is an arithmetic number, because the mean of its divisors is an integer number (333239200).

Almost surely, 2^666478399 is an apocalyptic number.

666478399 is a deficient number, since it is larger than the sum of its proper divisors (1).

666478399 is an equidigital number, since it uses as much as digits as its factorization.

666478399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11757312, while the sum is 58.

The square root of 666478399 is about 25816.2429295976. The cubic root of 666478399 is about 873.4982235163.

The spelling of 666478399 in words is "six hundred sixty-six million, four hundred seventy-eight thousand, three hundred ninety-nine".