1266665401 has 2 divisors, whose sum is σ = 1266665402. Its totient is φ = 1266665400.

The previous prime is 1266665383. The next prime is 1266665423. The reversal of 1266665401 is 1045666621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 826505001 + 440160400 = 28749^2 + 20980^2 .

It is a cyclic number.

It is not a de Polignac number, because 1266665401 - 2²⁹ = 729794489 is a prime.

It is not a weakly prime, because it can be changed into another prime (1266665431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633332700 + 633332701.

It is an arithmetic number, because the mean of its divisors is an integer number (633332701).

Almost surely, 2^1266665401 is an apocalyptic number.

It is an amenable number.

1266665401 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266665401 is an equidigital number, since it uses as much as digits as its factorization.

1266665401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 1266665401 is about 35590.2430590183. The cubic root of 1266665401 is about 1081.9834951465.

The spelling of 1266665401 in words is "one billion, two hundred sixty-six million, six hundred sixty-five thousand, four hundred one".