21680834 has 12 divisors (see below), whose sum is σ = 37831014. Its totient is φ = 9291744.

The previous prime is 21680833. The next prime is 21680849. The reversal of 21680834 is 43808612.

It can be written as a sum of positive squares in only one way, i.e., 12996025 + 8684809 = 3605^2 + 2947^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21680834.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680833) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 110519 + ... + 110714.

Almost surely, 2^21680834 is an apocalyptic number.

21680834 is a deficient number, since it is larger than the sum of its proper divisors (16150180).

21680834 is a wasteful number, since it uses less digits than its factorization.

21680834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221249 (or 221242 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 21680834 is about 4656.2682482864. The cubic root of 21680834 is about 278.8423032814.

The spelling of 21680834 in words is "twenty-one million, six hundred eighty thousand, eight hundred thirty-four".