21103564 has 12 divisors (see below), whose sum is σ = 37717344. Its totient is φ = 10327184.

The previous prime is 21103559. The next prime is 21103603. The reversal of 21103564 is 46530112.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55939 + ... + 56314.

It is an arithmetic number, because the mean of its divisors is an integer number (3143112).

Almost surely, 2^21103564 is an apocalyptic number.

It is an amenable number.

21103564 is a deficient number, since it is larger than the sum of its proper divisors (16613780).

21103564 is a wasteful number, since it uses less digits than its factorization.

21103564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112304 (or 112302 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21103564 is about 4593.8615564686. The cubic root of 21103564 is about 276.3452062255.

Adding to 21103564 its reverse (46530112), we get a palindrome (67633676).

The spelling of 21103564 in words is "twenty-one million, one hundred three thousand, five hundred sixty-four".