225785821 has 4 divisors (see below), whose sum is σ = 226151200. Its totient is φ = 225420444.

The previous prime is 225785773. The next prime is 225785849. The reversal of 225785821 is 128587522.

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 a cyclic number.

It is not a de Polignac number, because 225785821 - 2⁹ = 225785309 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 (225785881) 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 3 ways as a sum of consecutive naturals, for example, 181761 + ... + 182998.

It is an arithmetic number, because the mean of its divisors is an integer number (56537800).

Almost surely, 2^225785821 is an apocalyptic number.

It is an amenable number.

225785821 is a deficient number, since it is larger than the sum of its proper divisors (365379).

225785821 is an equidigital number, since it uses as much as digits as its factorization.

225785821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 365378.

The product of its digits is 89600, while the sum is 40.

The square root of 225785821 is about 15026.1712022724. The cubic root of 225785821 is about 608.9274541655.

The spelling of 225785821 in words is "two hundred twenty-five million, seven hundred eighty-five thousand, eight hundred twenty-one".