20311216 has 20 divisors (see below), whose sum is σ = 39853600. Its totient is φ = 10026432.

The previous prime is 20311211. The next prime is 20311273. The reversal of 20311216 is 61211302.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a self number, because there is not a number n which added to its sum of digits gives 20311216.

It is not an unprimeable number, because it can be changed into a prime (20311211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6771 + ... + 9298.

It is an arithmetic number, because the mean of its divisors is an integer number (1992680).

Almost surely, 2^20311216 is an apocalyptic number.

It is an amenable number.

20311216 is a deficient number, since it is larger than the sum of its proper divisors (19542384).

20311216 is a wasteful number, since it uses less digits than its factorization.

20311216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16156 (or 16150 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 20311216 is about 4506.7966450684. The cubic root of 20311216 is about 272.8424715222.

Adding to 20311216 its reverse (61211302), we get a palindrome (81522518).

The spelling of 20311216 in words is "twenty million, three hundred eleven thousand, two hundred sixteen".