24720221 has 2 divisors, whose sum is σ = 24720222. Its totient is φ = 24720220.

The previous prime is 24720211. The next prime is 24720229. The reversal of 24720221 is 12202742.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24700900 + 19321 = 4970^2 + 139^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-24720221 is a prime.

It is a super-2 number, since 2×24720221² = 1222178652577682, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 24720193 and 24720202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (24720229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12360110 + 12360111.

It is an arithmetic number, because the mean of its divisors is an integer number (12360111).

Almost surely, 2^24720221 is an apocalyptic number.

It is an amenable number.

24720221 is a deficient number, since it is larger than the sum of its proper divisors (1).

24720221 is an equidigital number, since it uses as much as digits as its factorization.

24720221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 24720221 is about 4971.9433826221. The cubic root of 24720221 is about 291.3069076542.

Adding to 24720221 its reverse (12202742), we get a palindrome (36922963).

The spelling of 24720221 in words is "twenty-four million, seven hundred twenty thousand, two hundred twenty-one".