21685465 has 8 divisors (see below), whose sum is σ = 26103168. Its totient is φ = 17294640.

The previous prime is 21685457. The next prime is 21685483. The reversal of 21685465 is 56458612.

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

It is not a de Polignac number, because 21685465 - 2³ = 21685457 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 4897 + ... + 8206.

It is an arithmetic number, because the mean of its divisors is an integer number (3262896).

Almost surely, 2^21685465 is an apocalyptic number.

It is an amenable number.

21685465 is a deficient number, since it is larger than the sum of its proper divisors (4417703).

21685465 is a wasteful number, since it uses less digits than its factorization.

21685465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13439.

The product of its digits is 57600, while the sum is 37.

The square root of 21685465 is about 4656.7655083760. The cubic root of 21685465 is about 278.8621553280.

The spelling of 21685465 in words is "twenty-one million, six hundred eighty-five thousand, four hundred sixty-five".