21648946 has 16 divisors (see below), whose sum is σ = 35779968. Its totient is φ = 9742000.

The previous prime is 21648941. The next prime is 21648947. The reversal of 21648946 is 64984612.

It is a junction number, because it is equal to n+sod(n) for n = 21648899 and 21648908.

It is not an unprimeable number, because it can be changed into a prime (21648941) 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 7 ways as a sum of consecutive naturals, for example, 2650 + ... + 7093.

It is an arithmetic number, because the mean of its divisors is an integer number (2236248).

Almost surely, 2^21648946 is an apocalyptic number.

21648946 is a deficient number, since it is larger than the sum of its proper divisors (14131022).

21648946 is a wasteful number, since it uses less digits than its factorization.

21648946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9857.

The product of its digits is 82944, while the sum is 40.

The square root of 21648946 is about 4652.8427869422. The cubic root of 21648946 is about 278.7055298494.

The spelling of 21648946 in words is "twenty-one million, six hundred forty-eight thousand, nine hundred forty-six".