266378989 has 4 divisors (see below), whose sum is σ = 267340924. Its totient is φ = 265417056.

The previous prime is 266378953. The next prime is 266379011. The reversal of 266378989 is 989873662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 989873662 = 2 ⋅494936831.

It can be written as a sum of positive squares in 2 ways, for example, as 114276100 + 152102889 = 10690^2 + 12333^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-266378989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266378929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 480552 + ... + 481105.

It is an arithmetic number, because the mean of its divisors is an integer number (66835231).

Almost surely, 2^266378989 is an apocalyptic number.

It is an amenable number.

266378989 is a deficient number, since it is larger than the sum of its proper divisors (961935).

266378989 is an equidigital number, since it uses as much as digits as its factorization.

266378989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 961934.

The product of its digits is 7838208, while the sum is 58.

The square root of 266378989 is about 16321.1209480231. The cubic root of 266378989 is about 643.4280483444.

The spelling of 266378989 in words is "two hundred sixty-six million, three hundred seventy-eight thousand, nine hundred eighty-nine".