21044819 has 4 divisors (see below), whose sum is σ = 21055944. Its totient is φ = 21033696.

The previous prime is 21044813. The next prime is 21044831. The reversal of 21044819 is 91844012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21044819 - 2²⁴ = 4267603 is a prime.

It is a super-2 number, since 2×21044819² = 885768813485522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21044791 and 21044800.

It is not an unprimeable number, because it can be changed into a prime (21044813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1937 + ... + 6770.

It is an arithmetic number, because the mean of its divisors is an integer number (5263986).

Almost surely, 2^21044819 is an apocalyptic number.

21044819 is a deficient number, since it is larger than the sum of its proper divisors (11125).

21044819 is an equidigital number, since it uses as much as digits as its factorization.

21044819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11124.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21044819 is about 4587.4632423596. The cubic root of 21044819 is about 276.0885515414.

The spelling of 21044819 in words is "twenty-one million, forty-four thousand, eight hundred nineteen".