266123891 has 6 divisors (see below), whose sum is σ = 292516476. Its totient is φ = 241930700.

The previous prime is 266123867. The next prime is 266123911. The reversal of 266123891 is 198321662.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-266123891 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (266123821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1099565 + ... + 1099806.

It is an arithmetic number, because the mean of its divisors is an integer number (48752746).

Almost surely, 2^266123891 is an apocalyptic number.

266123891 is a deficient number, since it is larger than the sum of its proper divisors (26392585).

266123891 is a wasteful number, since it uses less digits than its factorization.

266123891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2199393 (or 2199382 counting only the distinct ones).

The product of its digits is 31104, while the sum is 38.

The square root of 266123891 is about 16313.3041104492. The cubic root of 266123891 is about 643.2225896579. Note that the first 3 decimals are identical.

It can be divided in two parts, 26612 and 3891, that added together give a palindrome (30503).

The spelling of 266123891 in words is "two hundred sixty-six million, one hundred twenty-three thousand, eight hundred ninety-one".