225477821 has 2 divisors, whose sum is σ = 225477822. Its totient is φ = 225477820.

The previous prime is 225477803. The next prime is 225477823. The reversal of 225477821 is 128774522.

225477821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129163225 + 96314596 = 11365^2 + 9814^2 .

It is a cyclic number.

It is not a de Polignac number, because 225477821 - 2⁶ = 225477757 is a prime.

It is a Sophie Germain prime.

Together with 225477823, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (225477823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 112738910 + 112738911.

It is an arithmetic number, because the mean of its divisors is an integer number (112738911).

Almost surely, 2^225477821 is an apocalyptic number.

It is an amenable number.

225477821 is a deficient number, since it is larger than the sum of its proper divisors (1).

225477821 is an equidigital number, since it uses as much as digits as its factorization.

225477821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62720, while the sum is 38.

The square root of 225477821 is about 15015.9189196000. The cubic root of 225477821 is about 608.6504438553.

The spelling of 225477821 in words is "two hundred twenty-five million, four hundred seventy-seven thousand, eight hundred twenty-one".