21779846 has 16 divisors (see below), whose sum is σ = 35959248. Its totient is φ = 9811200.

The previous prime is 21779837. The next prime is 21779851. The reversal of 21779846 is 64897712.

It is a junction number, because it is equal to n+sod(n) for n = 21779797 and 21779806.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1895 + ... + 6866.

It is an arithmetic number, because the mean of its divisors is an integer number (2247453).

Almost surely, 2^21779846 is an apocalyptic number.

21779846 is a deficient number, since it is larger than the sum of its proper divisors (14179402).

21779846 is a wasteful number, since it uses less digits than its factorization.

21779846 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8887.

The product of its digits is 169344, while the sum is 44.

The square root of 21779846 is about 4666.8882566438. Note that the first 3 decimals coincide. The cubic root of 21779846 is about 279.2661309595.

The spelling of 21779846 in words is "twenty-one million, seven hundred seventy-nine thousand, eight hundred forty-six".