21680036 has 24 divisors (see below), whose sum is σ = 44760576. Its totient is φ = 8991360.

The previous prime is 21680027. The next prime is 21680059. The reversal of 21680036 is 63008612.

It is a super-2 number, since 2×21680036² = 940047921922592, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21679987 and 21680014.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11621 + ... + 13356.

It is an arithmetic number, because the mean of its divisors is an integer number (1865024).

Almost surely, 2^21680036 is an apocalyptic number.

It is an amenable number.

21680036 is an abundant number, since it is smaller than the sum of its proper divisors (23080540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21680036 is a wasteful number, since it uses less digits than its factorization.

21680036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25019 (or 25017 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21680036 is about 4656.1825565585. The cubic root of 21680036 is about 278.8388821509.

Adding to 21680036 its reverse (63008612), we get a palindrome (84688648).

The spelling of 21680036 in words is "twenty-one million, six hundred eighty thousand, thirty-six".