21816830 has 32 divisors (see below), whose sum is σ = 45109440. Its totient is φ = 7441920.

The previous prime is 21816803. The next prime is 21816841. The reversal of 21816830 is 3861812.

21816830 is nontrivially palindromic in base 6.

It is a junction number, because it is equal to n+sod(n) for n = 21816793 and 21816802.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15350 + ... + 16710.

It is an arithmetic number, because the mean of its divisors is an integer number (1409670).

Almost surely, 2^21816830 is an apocalyptic number.

21816830 is an abundant number, since it is smaller than the sum of its proper divisors (23292610).

21816830 is a wasteful number, since it uses less digits than its factorization.

21816830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1604.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21816830 is about 4670.8489592364. The cubic root of 21816830 is about 279.4241139857.

The spelling of 21816830 in words is "twenty-one million, eight hundred sixteen thousand, eight hundred thirty".