666566741 has 2 divisors, whose sum is σ = 666566742. Its totient is φ = 666566740.

The previous prime is 666566707. The next prime is 666566783. The reversal of 666566741 is 147665666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 658127716 + 8439025 = 25654^2 + 2905^2 .

It is a cyclic number.

It is not a de Polignac number, because 666566741 - 2¹⁰ = 666565717 is a prime.

It is a super-2 number, since 2×666566741² = 888622440414722162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666566701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333283370 + 333283371.

It is an arithmetic number, because the mean of its divisors is an integer number (333283371).

Almost surely, 2^666566741 is an apocalyptic number.

It is an amenable number.

666566741 is a deficient number, since it is larger than the sum of its proper divisors (1).

666566741 is an equidigital number, since it uses as much as digits as its factorization.

666566741 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 47.

The square root of 666566741 is about 25817.9538499859. The cubic root of 666566741 is about 873.5368160002.

The spelling of 666566741 in words is "six hundred sixty-six million, five hundred sixty-six thousand, seven hundred forty-one".