21012244 has 12 divisors (see below), whose sum is σ = 40114368. Its totient is φ = 9551000.

The previous prime is 21012241. The next prime is 21012259. The reversal of 21012244 is 44221012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012241) 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, 238732 + ... + 238819.

It is an arithmetic number, because the mean of its divisors is an integer number (3342864).

Almost surely, 2^21012244 is an apocalyptic number.

It is an amenable number.

21012244 is a deficient number, since it is larger than the sum of its proper divisors (19102124).

21012244 is a wasteful number, since it uses less digits than its factorization.

21012244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477566 (or 477564 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21012244 is about 4583.9114302089. The cubic root of 21012244 is about 275.9460266930.

Adding to 21012244 its reverse (44221012), we get a palindrome (65233256).

The spelling of 21012244 in words is "twenty-one million, twelve thousand, two hundred forty-four".