21042212 has 12 divisors (see below), whose sum is σ = 36889356. Its totient is φ = 10502400.

The previous prime is 21042193. The next prime is 21042223. The reversal of 21042212 is 21224012.

It can be written as a sum of positive squares in 2 ways, for example, as 18028516 + 3013696 = 4246^2 + 1736^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1973 + ... + 6780.

It is an arithmetic number, because the mean of its divisors is an integer number (3074113).

Almost surely, 2^21042212 is an apocalyptic number.

It is an amenable number.

21042212 is a deficient number, since it is larger than the sum of its proper divisors (15847144).

21042212 is a wasteful number, since it uses less digits than its factorization.

21042212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9358 (or 9356 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21042212 is about 4587.1790895931. The cubic root of 21042212 is about 276.0771505947.

Adding to 21042212 its reverse (21224012), we get a palindrome (42266224).

The spelling of 21042212 in words is "twenty-one million, forty-two thousand, two hundred twelve".