225615421 has 2 divisors, whose sum is σ = 225615422. Its totient is φ = 225615420.

The previous prime is 225615413. The next prime is 225615431. The reversal of 225615421 is 124516522.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216531225 + 9084196 = 14715^2 + 3014^2 .

It is a cyclic number.

It is not a de Polignac number, because 225615421 - 2³ = 225615413 is a prime.

It is the 15021-st Hogben number.

It is a self number, because there is not a number n which added to its sum of digits gives 225615421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (225615431) by changing a digit.

It is a nontrivial repunit in base 15020.

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 as a sum of consecutive naturals, namely, 112807710 + 112807711.

It is an arithmetic number, because the mean of its divisors is an integer number (112807711).

Almost surely, 2^225615421 is an apocalyptic number.

It is an amenable number.

225615421 is a deficient number, since it is larger than the sum of its proper divisors (1).

225615421 is an equidigital number, since it uses as much as digits as its factorization.

225615421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4800, while the sum is 28.

The square root of 225615421 is about 15020.5000249659. The cubic root of 225615421 is about 608.7742302659.

The spelling of 225615421 in words is "two hundred twenty-five million, six hundred fifteen thousand, four hundred twenty-one".