21465309 has 8 divisors (see below), whose sum is σ = 28723392. Its totient is φ = 14258720.

The previous prime is 21465289. The next prime is 21465313. The reversal of 21465309 is 90356412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21465309 - 2¹² = 21461213 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21465319) 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 7 ways as a sum of consecutive naturals, for example, 11889 + ... + 13574.

It is an arithmetic number, because the mean of its divisors is an integer number (3590424).

Almost surely, 2^21465309 is an apocalyptic number.

It is an amenable number.

21465309 is a deficient number, since it is larger than the sum of its proper divisors (7258083).

21465309 is a wasteful number, since it uses less digits than its factorization.

21465309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25747.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 21465309 is about 4633.0669108054. The cubic root of 21465309 is about 277.9152520170.

The spelling of 21465309 in words is "twenty-one million, four hundred sixty-five thousand, three hundred nine".