21840682 has 8 divisors (see below), whose sum is σ = 34688196. Its totient is φ = 10277952.

The previous prime is 21840673. The next prime is 21840691. The reversal of 21840682 is 28604812.

It is an interprime number because it is at equal distance from previous prime (21840673) and next prime (21840691).

It can be written as a sum of positive squares in 2 ways, for example, as 21335161 + 505521 = 4619^2 + 711^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 321153 + ... + 321220.

Almost surely, 2^21840682 is an apocalyptic number.

21840682 is a deficient number, since it is larger than the sum of its proper divisors (12847514).

21840682 is a wasteful number, since it uses less digits than its factorization.

21840682 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 642392.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 21840682 is about 4673.4015449135. The cubic root of 21840682 is about 279.5259069072.

It can be divided in two parts, 21840 and 682, that added together give a palindrome (22522).

The spelling of 21840682 in words is "twenty-one million, eight hundred forty thousand, six hundred eighty-two".