20606221217 has 4 divisors (see below), whose sum is σ = 20606692116. Its totient is φ = 20605750320.

The previous prime is 20606221187. The next prime is 20606221267. The reversal of 20606221217 is 71212260602.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18076533601 + 2529687616 = 134449^2 + 50296^2 .

It is a cyclic number.

It is not a de Polignac number, because 20606221217 - 2²⁶ = 20539112353 is a prime.

It is a super-2 number, since 2×20606221217² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20606221217.

It is not an unprimeable number, because it can be changed into a prime (20606221267) 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 in 3 ways as a sum of consecutive naturals, for example, 162218 + ... + 259859.

It is an arithmetic number, because the mean of its divisors is an integer number (5151673029).

Almost surely, 2^20606221217 is an apocalyptic number.

It is an amenable number.

20606221217 is a deficient number, since it is larger than the sum of its proper divisors (470899).

20606221217 is an equidigital number, since it uses as much as digits as its factorization.

20606221217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470898.

The product of its (nonzero) digits is 4032, while the sum is 29.

Adding to 20606221217 its reverse (71212260602), we get a palindrome (91818481819).

The spelling of 20606221217 in words is "twenty billion, six hundred six million, two hundred twenty-one thousand, two hundred seventeen".