21243040241 has 4 divisors (see below), whose sum is σ = 21975558900. Its totient is φ = 20510521584.

The previous prime is 21243040237. The next prime is 21243040249. The reversal of 21243040241 is 14204034212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14858391025 + 6384649216 = 121895^2 + 79904^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243040241 - 2² = 21243040237 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21243040249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 366259286 + ... + 366259343.

It is an arithmetic number, because the mean of its divisors is an integer number (5493889725).

Almost surely, 2^21243040241 is an apocalyptic number.

It is an amenable number.

21243040241 is a deficient number, since it is larger than the sum of its proper divisors (732518659).

21243040241 is an equidigital number, since it uses as much as digits as its factorization.

21243040241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732518658.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21243040241 its reverse (14204034212), we get a palindrome (35447074453).

The spelling of 21243040241 in words is "twenty-one billion, two hundred forty-three million, forty thousand, two hundred forty-one".