21022117 has 2 divisors, whose sum is σ = 21022118. Its totient is φ = 21022116.

The previous prime is 21022103. The next prime is 21022163. The reversal of 21022117 is 71122012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18931201 + 2090916 = 4351^2 + 1446^2 .

It is a cyclic number.

It is not a de Polignac number, because 21022117 - 2⁷ = 21021989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21022117.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21022517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511058 + 10511059.

It is an arithmetic number, because the mean of its divisors is an integer number (10511059).

Almost surely, 2^21022117 is an apocalyptic number.

It is an amenable number.

21022117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022117 is an equidigital number, since it uses as much as digits as its factorization.

21022117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 21022117 is about 4584.9882224494. The cubic root of 21022117 is about 275.9892394110.

Adding to 21022117 its reverse (71122012), we get a palindrome (92144129).

The spelling of 21022117 in words is "twenty-one million, twenty-two thousand, one hundred seventeen".