21016220217 has 8 divisors (see below), whose sum is σ = 28705081440. Its totient is φ = 13669086240.

The previous prime is 21016220213. The next prime is 21016220227. The reversal of 21016220217 is 71202261012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21016220217 - 2² = 21016220213 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21016220213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85431667 + ... + 85431912.

It is an arithmetic number, because the mean of its divisors is an integer number (3588135180).

Almost surely, 2^21016220217 is an apocalyptic number.

It is an amenable number.

21016220217 is a deficient number, since it is larger than the sum of its proper divisors (7688861223).

21016220217 is a wasteful number, since it uses less digits than its factorization.

21016220217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170863623.

The product of its (nonzero) digits is 672, while the sum is 24.

Adding to 21016220217 its reverse (71202261012), we get a palindrome (92218481229).

The spelling of 21016220217 in words is "twenty-one billion, sixteen million, two hundred twenty thousand, two hundred seventeen".