21639683 has 8 divisors (see below), whose sum is σ = 23410128. Its totient is φ = 19884384.

The previous prime is 21639679. The next prime is 21639701. The reversal of 21639683 is 38693612.

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

It is not a de Polignac number, because 21639683 - 2² = 21639679 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21639383) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 716 + ... + 6617.

It is an arithmetic number, because the mean of its divisors is an integer number (2926266).

Almost surely, 2^21639683 is an apocalyptic number.

21639683 is a deficient number, since it is larger than the sum of its proper divisors (1770445).

21639683 is a wasteful number, since it uses less digits than its factorization.

21639683 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7573.

The product of its digits is 46656, while the sum is 38.

The square root of 21639683 is about 4651.8472674842. The cubic root of 21639683 is about 278.6657739861.

It can be divided in two parts, 21639 and 683, that added together give a palindrome (22322).

The spelling of 21639683 in words is "twenty-one million, six hundred thirty-nine thousand, six hundred eighty-three".