21610818 has 24 divisors (see below), whose sum is σ = 47139456. Its totient is φ = 7155000.

The previous prime is 21610807. The next prime is 21610837. The reversal of 21610818 is 81801612.

It is a junction number, because it is equal to n+sod(n) for n = 21610791 and 21610800.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1258 + ... + 6693.

It is an arithmetic number, because the mean of its divisors is an integer number (1964144).

Almost surely, 2^21610818 is an apocalyptic number.

21610818 is an abundant number, since it is smaller than the sum of its proper divisors (25528638).

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

21610818 is a wasteful number, since it uses less digits than its factorization.

21610818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8110 (or 8107 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 21610818 is about 4648.7437012595. The cubic root of 21610818 is about 278.5418155053.

The spelling of 21610818 in words is "twenty-one million, six hundred ten thousand, eight hundred eighteen".