1266670021 has 2 divisors, whose sum is σ = 1266670022. Its totient is φ = 1266670020.

The previous prime is 1266669991. The next prime is 1266670057. The reversal of 1266670021 is 1200766621.

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., 1128019396 + 138650625 = 33586^2 + 11775^2 .

It is an emirp because it is prime and its reverse (1200766621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1266670021 - 2⁷ = 1266669893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1266679021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633335010 + 633335011.

It is an arithmetic number, because the mean of its divisors is an integer number (633335011).

Almost surely, 2^1266670021 is an apocalyptic number.

It is an amenable number.

1266670021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266670021 is an equidigital number, since it uses as much as digits as its factorization.

1266670021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 1266670021 is about 35590.3079643883. The cubic root of 1266670021 is about 1081.9848106104.

The spelling of 1266670021 in words is "one billion, two hundred sixty-six million, six hundred seventy thousand, twenty-one".