21102212 has 6 divisors (see below), whose sum is σ = 36928878. Its totient is φ = 10551104.

The previous prime is 21102209. The next prime is 21102239. The reversal of 21102212 is 21220112.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20647936 + 454276 = 4544^2 + 674^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21102193 and 21102202.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2637773 + ... + 2637780.

It is an arithmetic number, because the mean of its divisors is an integer number (6154813).

Almost surely, 2^21102212 is an apocalyptic number.

It is an amenable number.

21102212 is a deficient number, since it is larger than the sum of its proper divisors (15826666).

21102212 is a wasteful number, since it uses less digits than its factorization.

21102212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5275557 (or 5275555 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21102212 is about 4593.7144012226. The cubic root of 21102212 is about 276.3393047469.

Adding to 21102212 its reverse (21220112), we get a palindrome (42322324).

The spelling of 21102212 in words is "twenty-one million, one hundred two thousand, two hundred twelve".