21589471 has 2 divisors, whose sum is σ = 21589472. Its totient is φ = 21589470.

The previous prime is 21589459. The next prime is 21589481. The reversal of 21589471 is 17498512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21589471 is a prime.

It is a super-3 number, since 3×21589471³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 21589471.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21589481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10794735 + 10794736.

It is an arithmetic number, because the mean of its divisors is an integer number (10794736).

Almost surely, 2^21589471 is an apocalyptic number.

21589471 is a deficient number, since it is larger than the sum of its proper divisors (1).

21589471 is an equidigital number, since it uses as much as digits as its factorization.

21589471 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 37.

The square root of 21589471 is about 4646.4471373298. The cubic root of 21589471 is about 278.4500714688.

The spelling of 21589471 in words is "twenty-one million, five hundred eighty-nine thousand, four hundred seventy-one".