21243041 has 4 divisors (see below), whose sum is σ = 21255300. Its totient is φ = 21230784.

The previous prime is 21243023. The next prime is 21243049. The reversal of 21243041 is 14034212.

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 19324816 + 1918225 = 4396^2 + 1385^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243041 - 2²² = 17048737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21243049) 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, 2996 + ... + 7173.

It is an arithmetic number, because the mean of its divisors is an integer number (5313825).

Almost surely, 2^21243041 is an apocalyptic number.

It is an amenable number.

21243041 is a deficient number, since it is larger than the sum of its proper divisors (12259).

21243041 is a wasteful number, since it uses less digits than its factorization.

21243041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12258.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21243041 is about 4609.0173573116. The cubic root of 21243041 is about 276.9526738646.

Adding to 21243041 its reverse (14034212), we get a palindrome (35277253).

The spelling of 21243041 in words is "twenty-one million, two hundred forty-three thousand, forty-one".