20216216 has 16 divisors (see below), whose sum is σ = 39128640. Its totient is φ = 9781920.

The previous prime is 20216201. The next prime is 20216221. The reversal of 20216216 is 61261202.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40511 + ... + 41006.

It is an arithmetic number, because the mean of its divisors is an integer number (2445540).

Almost surely, 2^20216216 is an apocalyptic number.

It is an amenable number.

20216216 is a deficient number, since it is larger than the sum of its proper divisors (18912424).

20216216 is a wasteful number, since it uses less digits than its factorization.

20216216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81554 (or 81550 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 20216216 is about 4496.2446552651. The cubic root of 20216216 is about 272.4164252866.

Adding to 20216216 its reverse (61261202), we get a palindrome (81477418).

The spelling of 20216216 in words is "twenty million, two hundred sixteen thousand, two hundred sixteen".