666745523 has 2 divisors, whose sum is σ = 666745524. Its totient is φ = 666745522.

The previous prime is 666745501. The next prime is 666745553. The reversal of 666745523 is 325547666.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666745523 - 2¹⁴ = 666729139 is a prime.

It is not a weakly prime, because it can be changed into another prime (666745553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333372761 + 333372762.

It is an arithmetic number, because the mean of its divisors is an integer number (333372762).

Almost surely, 2^666745523 is an apocalyptic number.

666745523 is a deficient number, since it is larger than the sum of its proper divisors (1).

666745523 is an equidigital number, since it uses as much as digits as its factorization.

666745523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 907200, while the sum is 44.

The square root of 666745523 is about 25821.4159758910. The cubic root of 666745523 is about 873.6149070545.

The spelling of 666745523 in words is "six hundred sixty-six million, seven hundred forty-five thousand, five hundred twenty-three".