20321216 has 28 divisors (see below), whose sum is σ = 40614600. Its totient is φ = 10087680.

The previous prime is 20321201. The next prime is 20321233. The reversal of 20321216 is 61212302.

It is a junction number, because it is equal to n+sod(n) for n = 20321194 and 20321203.

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, 8471 + ... + 10601.

Almost surely, 2^20321216 is an apocalyptic number.

It is an amenable number.

20321216 is a deficient number, since it is larger than the sum of its proper divisors (20293384).

20321216 is a wasteful number, since it uses less digits than its factorization.

20321216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2292 (or 2282 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 20321216 is about 4507.9059440055. The cubic root of 20321216 is about 272.8872411554.

Adding to 20321216 its reverse (61212302), we get a palindrome (81533518).

It can be divided in two parts, 20 and 321216, that multiplied together give a triangular number (6424320 = T₃₅₈₄).

The spelling of 20321216 in words is "twenty million, three hundred twenty-one thousand, two hundred sixteen".