21589636 has 6 divisors (see below), whose sum is σ = 37781870. Its totient is φ = 10794816.

The previous prime is 21589627. The next prime is 21589637. The reversal of 21589636 is 63698512.

It can be written as a sum of positive squares in only one way, i.e., 17589636 + 4000000 = 4194^2 + 2000^2 .

It is a super-2 number, since 2×21589636² = 932224765224992, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21589637) 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 as a sum of consecutive naturals, namely, 2698701 + ... + 2698708.

Almost surely, 2^21589636 is an apocalyptic number.

It is an amenable number.

21589636 is a deficient number, since it is larger than the sum of its proper divisors (16192234).

21589636 is a wasteful number, since it uses less digits than its factorization.

21589636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5397413 (or 5397411 counting only the distinct ones).

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

The square root of 21589636 is about 4646.4648927975. The cubic root of 21589636 is about 278.4507808292.

The spelling of 21589636 in words is "twenty-one million, five hundred eighty-nine thousand, six hundred thirty-six".