1266120001 has 4 divisors (see below), whose sum is σ = 1266738772. Its totient is φ = 1265501232.

The previous prime is 1266119989. The next prime is 1266120017. The reversal of 1266120001 is 1000216621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1000216621 = 89 ⋅11238389.

It can be written as a sum of positive squares in 2 ways, for example, as 548683776 + 717436225 = 23424^2 + 26785^2 .

It is a cyclic number.

It is not a de Polignac number, because 1266120001 - 2⁵ = 1266119969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1266120041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 306306 + ... + 310411.

It is an arithmetic number, because the mean of its divisors is an integer number (316684693).

Almost surely, 2^1266120001 is an apocalyptic number.

It is an amenable number.

1266120001 is a deficient number, since it is larger than the sum of its proper divisors (618771).

1266120001 is an equidigital number, since it uses as much as digits as its factorization.

1266120001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 618770.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 1266120001 is about 35582.5800216904. The cubic root of 1266120001 is about 1081.8281795925.

Adding to 1266120001 its reverse (1000216621), we get a palindrome (2266336622).

The spelling of 1266120001 in words is "one billion, two hundred sixty-six million, one hundred twenty thousand, one".