666767957 has 2 divisors, whose sum is σ = 666767958. Its totient is φ = 666767956.

The previous prime is 666767939. The next prime is 666768001. The reversal of 666767957 is 759767666.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 516607441 + 150160516 = 22729^2 + 12254^2 .

It is a cyclic number.

It is not a de Polignac number, because 666767957 - 2¹⁸ = 666505813 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 666767896 and 666767905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666737957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333383978 + 333383979.

It is an arithmetic number, because the mean of its divisors is an integer number (333383979).

Almost surely, 2^666767957 is an apocalyptic number.

It is an amenable number.

666767957 is a deficient number, since it is larger than the sum of its proper divisors (1).

666767957 is an equidigital number, since it uses as much as digits as its factorization.

666767957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20003760, while the sum is 59.

The square root of 666767957 is about 25821.8503790879. The cubic root of 666767957 is about 873.6247051240.

The spelling of 666767957 in words is "six hundred sixty-six million, seven hundred sixty-seven thousand, nine hundred fifty-seven".