21662116 has 36 divisors (see below), whose sum is σ = 44688000. Its totient is φ = 9159696.

The previous prime is 21662059. The next prime is 21662117. The reversal of 21662116 is 61126612.

It is not an unprimeable number, because it can be changed into a prime (21662117) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14785 + ... + 16183.

Almost surely, 2^21662116 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21662116, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22344000).

21662116 is an abundant number, since it is smaller than the sum of its proper divisors (23025884).

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

21662116 is a wasteful number, since it uses less digits than its factorization.

21662116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1496 (or 1487 counting only the distinct ones).

The product of its digits is 864, while the sum is 25.

The square root of 21662116 is about 4654.2578355738. The cubic root of 21662116 is about 278.7620346443.

Adding to 21662116 its reverse (61126612), we get a palindrome (82788728).

The spelling of 21662116 in words is "twenty-one million, six hundred sixty-two thousand, one hundred sixteen".