21054017 has 2 divisors, whose sum is σ = 21054018. Its totient is φ = 21054016.

The previous prime is 21053987. The next prime is 21054037. The reversal of 21054017 is 71045012.

It is an a-pointer prime, because the next prime (21054037) can be obtained adding 21054017 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15713296 + 5340721 = 3964^2 + 2311^2 .

It is a cyclic number.

It is not a de Polignac number, because 21054017 - 2¹⁶ = 20988481 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21054017.

It is not a weakly prime, because it can be changed into another prime (21054037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10527008 + 10527009.

It is an arithmetic number, because the mean of its divisors is an integer number (10527009).

Almost surely, 2^21054017 is an apocalyptic number.

It is an amenable number.

21054017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21054017 is an equidigital number, since it uses as much as digits as its factorization.

21054017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21054017 is about 4588.4656476866. The cubic root of 21054017 is about 276.1287687656.

Adding to 21054017 its reverse (71045012), we get a palindrome (92099029).

The spelling of 21054017 in words is "twenty-one million, fifty-four thousand, seventeen".