266421 has 4 divisors (see below), whose sum is σ = 355232. Its totient is φ = 177612.

The previous prime is 266417. The next prime is 266447. The reversal of 266421 is 124662.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 266421 - 2² = 266417 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44401 + ... + 44406.

It is an arithmetic number, because the mean of its divisors is an integer number (88808).

2²⁶⁶⁴²¹ is an apocalyptic number.

It is an amenable number.

266421 is a deficient number, since it is larger than the sum of its proper divisors (88811).

266421 is an equidigital number, since it uses as much as digits as its factorization.

266421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88810.

The product of its digits is 576, while the sum is 21.

The square root of 266421 is about 516.1598589584. The cubic root of 266421 is about 64.3461871876.

The spelling of 266421 in words is "two hundred sixty-six thousand, four hundred twenty-one".