666397747 has 2 divisors, whose sum is σ = 666397748. Its totient is φ = 666397746.

The previous prime is 666397687. The next prime is 666397751. The reversal of 666397747 is 747793666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666397747 - 2⁷ = 666397619 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (666397447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333198873 + 333198874.

It is an arithmetic number, because the mean of its divisors is an integer number (333198874).

Almost surely, 2^666397747 is an apocalyptic number.

666397747 is a deficient number, since it is larger than the sum of its proper divisors (1).

666397747 is an equidigital number, since it uses as much as digits as its factorization.

666397747 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8001504, while the sum is 55.

The square root of 666397747 is about 25814.6808424974. The cubic root of 666397747 is about 873.4629874552.

The spelling of 666397747 in words is "six hundred sixty-six million, three hundred ninety-seven thousand, seven hundred forty-seven".