666727639 has 2 divisors, whose sum is σ = 666727640. Its totient is φ = 666727638.

The previous prime is 666727619. The next prime is 666727667. The reversal of 666727639 is 936727666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666727639 - 2⁷ = 666727511 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666727619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333363819 + 333363820.

It is an arithmetic number, because the mean of its divisors is an integer number (333363820).

Almost surely, 2^666727639 is an apocalyptic number.

666727639 is a deficient number, since it is larger than the sum of its proper divisors (1).

666727639 is an equidigital number, since it uses as much as digits as its factorization.

666727639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3429216, while the sum is 52.

The square root of 666727639 is about 25821.0696718784. The cubic root of 666727639 is about 873.6070960441.

The spelling of 666727639 in words is "six hundred sixty-six million, seven hundred twenty-seven thousand, six hundred thirty-nine".