21685883 has 4 divisors (see below), whose sum is σ = 21722568. Its totient is φ = 21649200.

The previous prime is 21685879. The next prime is 21685913. The reversal of 21685883 is 38858612.

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 21685883 - 2² = 21685879 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21685883.

It is not an unprimeable number, because it can be changed into a prime (21685483) 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, 17441 + ... + 18642.

It is an arithmetic number, because the mean of its divisors is an integer number (5430642).

Almost surely, 2^21685883 is an apocalyptic number.

21685883 is a deficient number, since it is larger than the sum of its proper divisors (36685).

21685883 is an equidigital number, since it uses as much as digits as its factorization.

21685883 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36684.

The product of its digits is 92160, while the sum is 41.

The square root of 21685883 is about 4656.8103890968. The cubic root of 21685883 is about 278.8639470601.

The spelling of 21685883 in words is "twenty-one million, six hundred eighty-five thousand, eight hundred eighty-three".