21384636 has 48 divisors (see below), whose sum is σ = 61415424. Its totient is φ = 5639616.

The previous prime is 21384619. The next prime is 21384647. The reversal of 21384636 is 63648312.

It is a junction number, because it is equal to n+sod(n) for n = 21384597 and 21384606.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8700 + ... + 10883.

It is an arithmetic number, because the mean of its divisors is an integer number (1279488).

Almost surely, 2^21384636 is an apocalyptic number.

21384636 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21384636 is an abundant number, since it is smaller than the sum of its proper divisors (40030788).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21384636 is a wasteful number, since it uses less digits than its factorization.

21384636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19610 (or 19608 counting only the distinct ones).

The product of its digits is 20736, while the sum is 33.

The square root of 21384636 is about 4624.3524952149. The cubic root of 21384636 is about 277.5666522795.

The spelling of 21384636 in words is "twenty-one million, three hundred eighty-four thousand, six hundred thirty-six".