21221201117 has 2 divisors, whose sum is σ = 21221201118. Its totient is φ = 21221201116.

The previous prime is 21221201087. The next prime is 21221201129. The reversal of 21221201117 is 71110212212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13878253636 + 7342947481 = 117806^2 + 85691^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221201117 - 2¹² = 21221197021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221201317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610600558 + 10610600559.

It is an arithmetic number, because the mean of its divisors is an integer number (10610600559).

Almost surely, 2^21221201117 is an apocalyptic number.

It is an amenable number.

21221201117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221201117 is an equidigital number, since it uses as much as digits as its factorization.

21221201117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 20.

Adding to 21221201117 its reverse (71110212212), we get a palindrome (92331413329).

The spelling of 21221201117 in words is "twenty-one billion, two hundred twenty-one million, two hundred one thousand, one hundred seventeen".