21456589 has 16 divisors (see below), whose sum is σ = 27210240. Its totient is φ = 16432560.

The previous prime is 21456583. The next prime is 21456593. The reversal of 21456589 is 98565412.

It is a cyclic number.

It is not a de Polignac number, because 21456589 - 2⁹ = 21456077 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

Its product of digits (86400) is a multiple of the sum of its prime divisors (4800).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456583) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2182 + ... + 6904.

It is an arithmetic number, because the mean of its divisors is an integer number (1700640).

Almost surely, 2^21456589 is an apocalyptic number.

It is an amenable number.

21456589 is a deficient number, since it is larger than the sum of its proper divisors (5753651).

21456589 is a wasteful number, since it uses less digits than its factorization.

21456589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4800.

The product of its digits is 86400, while the sum is 40.

The square root of 21456589 is about 4632.1257539061. The cubic root of 21456589 is about 277.8776137789.

The spelling of 21456589 in words is "twenty-one million, four hundred fifty-six thousand, five hundred eighty-nine".