21816316 has 6 divisors (see below), whose sum is σ = 38178560. Its totient is φ = 10908156.

The previous prime is 21816307. The next prime is 21816317. The reversal of 21816316 is 61361812.

It is a pancake number, because a pancake can be divided into 21816316 parts by 6605 straight cuts.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21816317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2727036 + ... + 2727043.

Almost surely, 2^21816316 is an apocalyptic number.

It is an amenable number.

21816316 is a deficient number, since it is larger than the sum of its proper divisors (16362244).

21816316 is a wasteful number, since it uses less digits than its factorization.

21816316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5454083 (or 5454081 counting only the distinct ones).

The product of its digits is 1728, while the sum is 28.

The square root of 21816316 is about 4670.7939367949. The cubic root of 21816316 is about 279.4219195770.

The spelling of 21816316 in words is "twenty-one million, eight hundred sixteen thousand, three hundred sixteen".