21589643 has 8 divisors (see below), whose sum is σ = 24063120. Its totient is φ = 19249920.

The previous prime is 21589639. The next prime is 21589651. The reversal of 21589643 is 34698512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21589643 - 2² = 21589639 is a prime.

It is a super-2 number, since 2×21589643² = 932225369734898, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21589597 and 21589606.

It is not an unprimeable number, because it can be changed into a prime (21589943) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 33098 + ... + 33743.

It is an arithmetic number, because the mean of its divisors is an integer number (3007890).

Almost surely, 2^21589643 is an apocalyptic number.

21589643 is a deficient number, since it is larger than the sum of its proper divisors (2473477).

21589643 is a wasteful number, since it uses less digits than its factorization.

21589643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66877.

The product of its digits is 51840, while the sum is 38.

The square root of 21589643 is about 4646.4656460583. The cubic root of 21589643 is about 278.4508109231.

The spelling of 21589643 in words is "twenty-one million, five hundred eighty-nine thousand, six hundred forty-three".