21436241 has 2 divisors, whose sum is σ = 21436242. Its totient is φ = 21436240.

The previous prime is 21436229. The next prime is 21436243. The reversal of 21436241 is 14263412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14984641 + 6451600 = 3871^2 + 2540^2 .

It is a cyclic number.

It is not a de Polignac number, because 21436241 - 2¹⁴ = 21419857 is a prime.

Together with 21436243, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21436243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10718120 + 10718121.

It is an arithmetic number, because the mean of its divisors is an integer number (10718121).

Almost surely, 2^21436241 is an apocalyptic number.

It is an amenable number.

21436241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21436241 is an equidigital number, since it uses as much as digits as its factorization.

21436241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 23.

The square root of 21436241 is about 4629.9288331464. The cubic root of 21436241 is about 277.7897457895.

Adding to 21436241 its reverse (14263412), we get a palindrome (35699653).

The spelling of 21436241 in words is "twenty-one million, four hundred thirty-six thousand, two hundred forty-one".