21104842 has 16 divisors (see below), whose sum is σ = 34605792. Its totient is φ = 9573520.

The previous prime is 21104819. The next prime is 21104843. The reversal of 21104842 is 24840112.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (21104843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20328 + ... + 21340.

It is an arithmetic number, because the mean of its divisors is an integer number (2162862).

Almost surely, 2^21104842 is an apocalyptic number.

21104842 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21104842 is a deficient number, since it is larger than the sum of its proper divisors (13500950).

21104842 is a wasteful number, since it uses less digits than its factorization.

21104842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1973.

The product of its (nonzero) digits is 512, while the sum is 22.

The square root of 21104842 is about 4594.0006530256. Note that the first 3 decimals coincide. The cubic root of 21104842 is about 276.3507844625.

Adding to 21104842 its reverse (24840112), we get a palindrome (45944954).

The spelling of 21104842 in words is "twenty-one million, one hundred four thousand, eight hundred forty-two".