20001216 has 28 divisors (see below), whose sum is σ = 52920392. Its totient is φ = 6667008.

The previous prime is 20001203. The next prime is 20001217. The reversal of 20001216 is 61210002.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51895 + ... + 52278.

It is an arithmetic number, because the mean of its divisors is an integer number (1890014).

Almost surely, 2^20001216 is an apocalyptic number.

It is an amenable number.

20001216 is an abundant number, since it is smaller than the sum of its proper divisors (32919176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20001216 is a wasteful number, since it uses less digits than its factorization.

20001216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104188 (or 104178 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 20001216 is about 4472.2719058662. The cubic root of 20001216 is about 271.4472627677.

Adding to 20001216 its reverse (61210002), we get a palindrome (81211218).

It can be divided in two parts, 200012 and 16, that added together give a triangular number (200028 = T₆₃₂).

The spelling of 20001216 in words is "twenty million, one thousand, two hundred sixteen".