21089465 has 4 divisors (see below), whose sum is σ = 25307364. Its totient is φ = 16871568.

The previous prime is 21089437. The next prime is 21089473. The reversal of 21089465 is 56498012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11002489 + 10086976 = 3317^2 + 3176^2 .

It is a cyclic number.

It is not a de Polignac number, because 21089465 - 2⁸ = 21089209 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2108942 + ... + 2108951.

It is an arithmetic number, because the mean of its divisors is an integer number (6326841).

Almost surely, 2^21089465 is an apocalyptic number.

It is an amenable number.

21089465 is a deficient number, since it is larger than the sum of its proper divisors (4217899).

21089465 is an equidigital number, since it uses as much as digits as its factorization.

21089465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4217898.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 21089465 is about 4592.3267523119. The cubic root of 21089465 is about 276.2836517088.

The spelling of 21089465 in words is "twenty-one million, eighty-nine thousand, four hundred sixty-five".