21683607 has 8 divisors (see below), whose sum is σ = 31539840. Its totient is φ = 13141560.

The previous prime is 21683603. The next prime is 21683611. The reversal of 21683607 is 70638612.

It is an interprime number because it is at equal distance from previous prime (21683603) and next prime (21683611).

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

It is not a de Polignac number, because 21683607 - 2² = 21683603 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 657079 = 21683607 / (2 + 1 + 6 + 8 + 3 + 6 + 0 + 7).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21683603) 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, 328507 + ... + 328572.

It is an arithmetic number, because the mean of its divisors is an integer number (3942480).

Almost surely, 2^21683607 is an apocalyptic number.

21683607 is a deficient number, since it is larger than the sum of its proper divisors (9856233).

21683607 is a wasteful number, since it uses less digits than its factorization.

21683607 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657093.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 21683607 is about 4656.5660094108. The cubic root of 21683607 is about 278.8541908430.

It can be divided in two parts, 2168 and 3607, that added together give a palindrome (5775).

The spelling of 21683607 in words is "twenty-one million, six hundred eighty-three thousand, six hundred seven".