21559411 has 4 divisors (see below), whose sum is σ = 21574800. Its totient is φ = 21544024.

The previous prime is 21559409. The next prime is 21559423. The reversal of 21559411 is 11495512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21559411 - 2¹ = 21559409 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21559411.

It is not an unprimeable number, because it can be changed into a prime (21529411) 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 3 ways as a sum of consecutive naturals, for example, 5356 + ... + 8473.

It is an arithmetic number, because the mean of its divisors is an integer number (5393700).

Almost surely, 2^21559411 is an apocalyptic number.

21559411 is a deficient number, since it is larger than the sum of its proper divisors (15389).

21559411 is a wasteful number, since it uses less digits than its factorization.

21559411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15388.

The product of its digits is 1800, while the sum is 28.

The square root of 21559411 is about 4643.2112809994. The cubic root of 21559411 is about 278.3207785541.

The spelling of 21559411 in words is "twenty-one million, five hundred fifty-nine thousand, four hundred eleven".