21159836 has 6 divisors (see below), whose sum is σ = 37029720. Its totient is φ = 10579916.

The previous prime is 21159811. The next prime is 21159857. The reversal of 21159836 is 63895112.

It is a junction number, because it is equal to n+sod(n) for n = 21159796 and 21159805.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2644976 + ... + 2644983.

It is an arithmetic number, because the mean of its divisors is an integer number (6171620).

Almost surely, 2^21159836 is an apocalyptic number.

It is an amenable number.

21159836 is a deficient number, since it is larger than the sum of its proper divisors (15869884).

21159836 is a wasteful number, since it uses less digits than its factorization.

21159836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5289963 (or 5289961 counting only the distinct ones).

The product of its digits is 12960, while the sum is 35.

The square root of 21159836 is about 4599.9821738785. The cubic root of 21159836 is about 276.5906102126.

The spelling of 21159836 in words is "twenty-one million, one hundred fifty-nine thousand, eight hundred thirty-six".