21005041 has 2 divisors, whose sum is σ = 21005042. Its totient is φ = 21005040.

The previous prime is 21005029. The next prime is 21005053. The reversal of 21005041 is 14050012.

It is a balanced prime because it is at equal distance from previous prime (21005029) and next prime (21005053).

It can be written as a sum of positive squares in only one way, i.e., 18524416 + 2480625 = 4304^2 + 1575^2 .

It is a cyclic number.

It is not a de Polignac number, because 21005041 - 2⁵ = 21005009 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21005441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502520 + 10502521.

It is an arithmetic number, because the mean of its divisors is an integer number (10502521).

Almost surely, 2^21005041 is an apocalyptic number.

It is an amenable number.

21005041 is a deficient number, since it is larger than the sum of its proper divisors (1).

21005041 is an equidigital number, since it uses as much as digits as its factorization.

21005041 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 21005041 is about 4583.1256801445. The cubic root of 21005041 is about 275.9144916446.

Adding to 21005041 its reverse (14050012), we get a palindrome (35055053).

The spelling of 21005041 in words is "twenty-one million, five thousand, forty-one".