21221001220117 has 2 divisors, whose sum is σ = 21221001220118. Its totient is φ = 21221001220116.

The previous prime is 21221001220109. The next prime is 21221001220147. The reversal of 21221001220117 is 71102210012212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19779642499761 + 1441358720356 = 4447431^2 + 1200566^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221001220117 - 2³ = 21221001220109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221001220147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610500610058 + 10610500610059.

It is an arithmetic number, because the mean of its divisors is an integer number (10610500610059).

Almost surely, 2^{21221001220117} is an apocalyptic number.

It is an amenable number.

21221001220117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221001220117 is an equidigital number, since it uses as much as digits as its factorization.

21221001220117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 224, while the sum is 22.

Adding to 21221001220117 its reverse (71102210012212), we get a palindrome (92323211232329).

The spelling of 21221001220117 in words is "twenty-one trillion, two hundred twenty-one billion, one million, two hundred twenty thousand, one hundred seventeen".