21438017 has 2 divisors, whose sum is σ = 21438018. Its totient is φ = 21438016.

The previous prime is 21438013. The next prime is 21438029. The reversal of 21438017 is 71083412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17272336 + 4165681 = 4156^2 + 2041^2 .

It is a cyclic number.

It is not a de Polignac number, because 21438017 - 2² = 21438013 is a prime.

It is a plaindrome in base 11.

It is not a weakly prime, because it can be changed into another prime (21438013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10719008 + 10719009.

It is an arithmetic number, because the mean of its divisors is an integer number (10719009).

Almost surely, 2^21438017 is an apocalyptic number.

It is an amenable number.

21438017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21438017 is an equidigital number, since it uses as much as digits as its factorization.

21438017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 21438017 is about 4630.1206247786. The cubic root of 21438017 is about 277.7974172366.

The spelling of 21438017 in words is "twenty-one million, four hundred thirty-eight thousand, seventeen".