242657221 has 2 divisors, whose sum is σ = 242657222. Its totient is φ = 242657220.

The previous prime is 242657209. The next prime is 242657281. The reversal of 242657221 is 122756242.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 222308100 + 20349121 = 14910^2 + 4511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-242657221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (242657281) 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, 121328610 + 121328611.

It is an arithmetic number, because the mean of its divisors is an integer number (121328611).

Almost surely, 2^242657221 is an apocalyptic number.

It is an amenable number.

242657221 is a deficient number, since it is larger than the sum of its proper divisors (1).

242657221 is an equidigital number, since it uses as much as digits as its factorization.

242657221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 31.

The square root of 242657221 is about 15577.4587465350. The cubic root of 242657221 is about 623.7315894770.

The spelling of 242657221 in words is "two hundred forty-two million, six hundred fifty-seven thousand, two hundred twenty-one".