247221 has 12 divisors (see below), whose sum is σ = 384748. Its totient is φ = 152064.

The previous prime is 247201. The next prime is 247223. The reversal of 247221 is 122742.

It can be written as a sum of positive squares in 2 ways, for example, as 11025 + 236196 = 105^2 + 486^2 .

It is not a de Polignac number, because 247221 - 2⁹ = 246709 is a prime.

It is a super-2 number, since 2×247221² = 122236445682, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 247194 and 247203.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 247221.

It is not an unprimeable number, because it can be changed into a prime (247223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 940 + ... + 1173.

2²⁴⁷²²¹ is an apocalyptic number.

It is an amenable number.

247221 is a deficient number, since it is larger than the sum of its proper divisors (137527).

247221 is a wasteful number, since it uses less digits than its factorization.

247221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2132 (or 2129 counting only the distinct ones).

The product of its digits is 224, while the sum is 18.

The square root of 247221 is about 497.2132339349. The cubic root of 247221 is about 62.7617608364.

Adding to 247221 its reverse (122742), we get a palindrome (369963).

The spelling of 247221 in words is "two hundred forty-seven thousand, two hundred twenty-one", and thus it is an iban number.