21563896 has 32 divisors (see below), whose sum is σ = 41833440. Its totient is φ = 10412928.

The previous prime is 21563891. The next prime is 21563897. The reversal of 21563896 is 69836512.

It is a super-2 number, since 2×21563896² = 930003221397632, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21563891) 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, 77710 + ... + 77986.

It is an arithmetic number, because the mean of its divisors is an integer number (1307295).

Almost surely, 2^21563896 is an apocalyptic number.

It is an amenable number.

21563896 is a deficient number, since it is larger than the sum of its proper divisors (20269544).

21563896 is a wasteful number, since it uses less digits than its factorization.

21563896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583 (or 579 counting only the distinct ones).

The product of its digits is 77760, while the sum is 40.

The square root of 21563896 is about 4643.6942190459. The cubic root of 21563896 is about 278.3400768881.

The spelling of 21563896 in words is "twenty-one million, five hundred sixty-three thousand, eight hundred ninety-six".