21424241 has 2 divisors, whose sum is σ = 21424242. Its totient is φ = 21424240.

The previous prime is 21424223. The next prime is 21424253. The reversal of 21424241 is 14242412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16000000 + 5424241 = 4000^2 + 2329^2 .

It is a cyclic number.

It is not a de Polignac number, because 21424241 - 2²² = 17229937 is a prime.

It is not a weakly prime, because it can be changed into another prime (21424261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712120 + 10712121.

It is an arithmetic number, because the mean of its divisors is an integer number (10712121).

Almost surely, 2^21424241 is an apocalyptic number.

It is an amenable number.

21424241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21424241 is an equidigital number, since it uses as much as digits as its factorization.

21424241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 512, while the sum is 20.

The square root of 21424241 is about 4628.6327354846. The cubic root of 21424241 is about 277.7379005808.

Adding to 21424241 its reverse (14242412), we get a palindrome (35666653).

It can be divided in two parts, 2 and 1424241, that multiplied together give a palindrome (2848482).

The spelling of 21424241 in words is "twenty-one million, four hundred twenty-four thousand, two hundred forty-one".