21089459 has 4 divisors (see below), whose sum is σ = 22006416. Its totient is φ = 20172504.

The previous prime is 21089437. The next prime is 21089473. The reversal of 21089459 is 95498012.

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 21089459 - 2⁸ = 21089203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21089489) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 458444 + ... + 458489.

It is an arithmetic number, because the mean of its divisors is an integer number (5501604).

Almost surely, 2^21089459 is an apocalyptic number.

21089459 is a deficient number, since it is larger than the sum of its proper divisors (916957).

21089459 is an equidigital number, since it uses as much as digits as its factorization.

21089459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916956.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 21089459 is about 4592.3260990483. The cubic root of 21089459 is about 276.2836255077.

The spelling of 21089459 in words is "twenty-one million, eighty-nine thousand, four hundred fifty-nine".