225391921 has 2 divisors, whose sum is σ = 225391922. Its totient is φ = 225391920.

The previous prime is 225391891. The next prime is 225391937. The reversal of 225391921 is 129193522.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 222010000 + 3381921 = 14900^2 + 1839^2 .

It is a cyclic number.

It is not a de Polignac number, because 225391921 - 2⁹ = 225391409 is a prime.

It is not a weakly prime, because it can be changed into another prime (225391981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 112695960 + 112695961.

It is an arithmetic number, because the mean of its divisors is an integer number (112695961).

Almost surely, 2^225391921 is an apocalyptic number.

It is an amenable number.

225391921 is a deficient number, since it is larger than the sum of its proper divisors (1).

225391921 is an equidigital number, since it uses as much as digits as its factorization.

225391921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9720, while the sum is 34.

The square root of 225391921 is about 15013.0583493171. The cubic root of 225391921 is about 608.5731417749.

The spelling of 225391921 in words is "two hundred twenty-five million, three hundred ninety-one thousand, nine hundred twenty-one".