225787721 has 2 divisors, whose sum is σ = 225787722. Its totient is φ = 225787720.

The previous prime is 225787703. The next prime is 225787729. The reversal of 225787721 is 127787522.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 217975696 + 7812025 = 14764^2 + 2795^2 .

It is a cyclic number.

It is not a de Polignac number, because 225787721 - 2²² = 221593417 is a prime.

It is not a weakly prime, because it can be changed into another prime (225787729) 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 as a sum of consecutive naturals, namely, 112893860 + 112893861.

It is an arithmetic number, because the mean of its divisors is an integer number (112893861).

Almost surely, 2^225787721 is an apocalyptic number.

It is an amenable number.

225787721 is a deficient number, since it is larger than the sum of its proper divisors (1).

225787721 is an equidigital number, since it uses as much as digits as its factorization.

225787721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 109760, while the sum is 41.

The square root of 225787721 is about 15026.2344251645. The cubic root of 225787721 is about 608.9291622133.

The spelling of 225787721 in words is "two hundred twenty-five million, seven hundred eighty-seven thousand, seven hundred twenty-one".