21000041 has 2 divisors, whose sum is σ = 21000042. Its totient is φ = 21000040.

The previous prime is 21000037. The next prime is 21000059. The reversal of 21000041 is 14000012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20286016 + 714025 = 4504^2 + 845^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000041 - 2² = 21000037 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20999992 and 21000028.

It is not a weakly prime, because it can be changed into another prime (21005041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500020 + 10500021.

It is an arithmetic number, because the mean of its divisors is an integer number (10500021).

Almost surely, 2^21000041 is an apocalyptic number.

It is an amenable number.

21000041 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000041 is an equidigital number, since it uses as much as digits as its factorization.

21000041 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 21000041 is about 4582.5801684204. The cubic root of 21000041 is about 275.8925971870.

Adding to 21000041 its reverse (14000012), we get a palindrome (35000053).

The spelling of 21000041 in words is "twenty-one million, forty-one", and thus it is an aban number and an uban number.