238656221 has 2 divisors, whose sum is σ = 238656222. Its totient is φ = 238656220.

The previous prime is 238656139. The next prime is 238656247. The reversal of 238656221 is 122656832.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151905625 + 86750596 = 12325^2 + 9314^2 .

It is a cyclic number.

It is not a de Polignac number, because 238656221 - 2²² = 234461917 is a prime.

It is a Sophie Germain 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 (238652221) 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, 119328110 + 119328111.

It is an arithmetic number, because the mean of its divisors is an integer number (119328111).

Almost surely, 2^238656221 is an apocalyptic number.

It is an amenable number.

238656221 is a deficient number, since it is larger than the sum of its proper divisors (1).

238656221 is an equidigital number, since it uses as much as digits as its factorization.

238656221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 35.

The square root of 238656221 is about 15448.5022251350. The cubic root of 238656221 is about 620.2844870290.

The spelling of 238656221 in words is "two hundred thirty-eight million, six hundred fifty-six thousand, two hundred twenty-one".