21012242 has 8 divisors (see below), whose sum is σ = 31830732. Its totient is φ = 10402000.

The previous prime is 21012241. The next prime is 21012259. The reversal of 21012242 is 24221012.

It can be written as a sum of positive squares in 2 ways, for example, as 17732521 + 3279721 = 4211^2 + 1811^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

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, 51809 + ... + 52212.

Almost surely, 2^21012242 is an apocalyptic number.

21012242 is a deficient number, since it is larger than the sum of its proper divisors (10818490).

21012242 is a wasteful number, since it uses less digits than its factorization.

21012242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104124.

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

The square root of 21012242 is about 4583.9112120546. The cubic root of 21012242 is about 275.9460179379.

Adding to 21012242 its reverse (24221012), we get a palindrome (45233254).

The spelling of 21012242 in words is "twenty-one million, twelve thousand, two hundred forty-two".