21242042 has 8 divisors (see below), whose sum is σ = 31882656. Its totient is φ = 10614492.

The previous prime is 21241991. The next prime is 21242047. The reversal of 21242042 is 24024212.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21242042.

It is not an unprimeable number, because it can be changed into a prime (21242047) 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, 4403 + ... + 7865.

It is an arithmetic number, because the mean of its divisors is an integer number (3985332).

Almost surely, 2^21242042 is an apocalyptic number.

21242042 is a deficient number, since it is larger than the sum of its proper divisors (10640614).

21242042 is a wasteful number, since it uses less digits than its factorization.

21242042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6532.

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21242042 is about 4608.9089815270. The cubic root of 21242042 is about 276.9483323635.

Adding to 21242042 its reverse (24024212), we get a palindrome (45266254).

The spelling of 21242042 in words is "twenty-one million, two hundred forty-two thousand, forty-two".