21116212 has 18 divisors (see below), whose sum is σ = 40015878. Its totient is φ = 9745632.

The previous prime is 21116209. The next prime is 21116213. The reversal of 21116212 is 21261112.

It can be written as a sum of positive squares in 3 ways, for example, as 992016 + 20124196 = 996^2 + 4486^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21116213) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14943 + ... + 16294.

Almost surely, 2^21116212 is an apocalyptic number.

It is an amenable number.

21116212 is a deficient number, since it is larger than the sum of its proper divisors (18899666).

21116212 is a wasteful number, since it uses less digits than its factorization.

21116212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31267 (or 31252 counting only the distinct ones).

The product of its digits is 48, while the sum is 16.

The square root of 21116212 is about 4595.2379698988. The cubic root of 21116212 is about 276.4004025285.

Adding to 21116212 its reverse (21261112), we get a palindrome (42377324).

The spelling of 21116212 in words is "twenty-one million, one hundred sixteen thousand, two hundred twelve".