21620117 has 2 divisors, whose sum is σ = 21620118. Its totient is φ = 21620116.

The previous prime is 21620111. The next prime is 21620129. The reversal of 21620117 is 71102612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20557156 + 1062961 = 4534^2 + 1031^2 .

It is a cyclic number.

It is not a de Polignac number, because 21620117 - 2⁴ = 21620101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21620111) 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, 10810058 + 10810059.

It is an arithmetic number, because the mean of its divisors is an integer number (10810059).

Almost surely, 2^21620117 is an apocalyptic number.

It is an amenable number.

21620117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620117 is an equidigital number, since it uses as much as digits as its factorization.

21620117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 21620117 is about 4649.7437563806. The cubic root of 21620117 is about 278.5817613775.

Adding to 21620117 its reverse (71102612), we get a palindrome (92722729).

The spelling of 21620117 in words is "twenty-one million, six hundred twenty thousand, one hundred seventeen".