655145221 has 2 divisors, whose sum is σ = 655145222. Its totient is φ = 655145220.

The previous prime is 655145159. The next prime is 655145261. The reversal of 655145221 is 122541556.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 419676196 + 235469025 = 20486^2 + 15345^2 .

It is a cyclic number.

It is not a de Polignac number, because 655145221 - 2⁷ = 655145093 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (655145261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 327572610 + 327572611.

It is an arithmetic number, because the mean of its divisors is an integer number (327572611).

Almost surely, 2^655145221 is an apocalyptic number.

It is an amenable number.

655145221 is a deficient number, since it is larger than the sum of its proper divisors (1).

655145221 is an equidigital number, since it uses as much as digits as its factorization.

655145221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12000, while the sum is 31.

The square root of 655145221 is about 25595.8047539045. The cubic root of 655145221 is about 868.5187376357.

Adding to 655145221 its reverse (122541556), we get a palindrome (777686777).

The spelling of 655145221 in words is "six hundred fifty-five million, one hundred forty-five thousand, two hundred twenty-one".