255804821 has 4 divisors (see below), whose sum is σ = 258337644. Its totient is φ = 253272000.

The previous prime is 255804803. The next prime is 255804841. The reversal of 255804821 is 128408552.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 151560721 + 104244100 = 12311^2 + 10210^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-255804821 is a prime.

It is a super-2 number, since 2×255804821² = 130872212893684082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255804841) 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, 1266260 + ... + 1266461.

It is an arithmetic number, because the mean of its divisors is an integer number (64584411).

Almost surely, 2^255804821 is an apocalyptic number.

It is an amenable number.

255804821 is a deficient number, since it is larger than the sum of its proper divisors (2532823).

255804821 is a wasteful number, since it uses less digits than its factorization.

255804821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2532822.

The product of its (nonzero) digits is 25600, while the sum is 35.

The square root of 255804821 is about 15993.8994932443. The cubic root of 255804821 is about 634.7990113484.

The spelling of 255804821 in words is "two hundred fifty-five million, eight hundred four thousand, eight hundred twenty-one".