21682417 has 2 divisors, whose sum is σ = 21682418. Its totient is φ = 21682416.

The previous prime is 21682403. The next prime is 21682433. The reversal of 21682417 is 71428612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15046641 + 6635776 = 3879^2 + 2576^2 .

It is a cyclic number.

It is not a de Polignac number, because 21682417 - 2⁷ = 21682289 is a prime.

It is not a weakly prime, because it can be changed into another prime (21682487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10841208 + 10841209.

It is an arithmetic number, because the mean of its divisors is an integer number (10841209).

Almost surely, 2^21682417 is an apocalyptic number.

It is an amenable number.

21682417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21682417 is an equidigital number, since it uses as much as digits as its factorization.

21682417 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5376, while the sum is 31.

The square root of 21682417 is about 4656.4382310947. The cubic root of 21682417 is about 278.8490895613.

The spelling of 21682417 in words is "twenty-one million, six hundred eighty-two thousand, four hundred seventeen".