21662016 has 56 divisors (see below), whose sum is σ = 57668160. Its totient is φ = 7176192.

The previous prime is 21661999. The next prime is 21662041. The reversal of 21662016 is 61026612.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49125 + ... + 49563.

Almost surely, 2^21662016 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 21662016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28834080).

21662016 is an abundant number, since it is smaller than the sum of its proper divisors (36006144).

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

21662016 is a wasteful number, since it uses less digits than its factorization.

21662016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 711 (or 701 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 21662016 is about 4654.2470927101. The cubic root of 21662016 is about 278.7616056889.

Adding to 21662016 its reverse (61026612), we get a palindrome (82688628).

The spelling of 21662016 in words is "twenty-one million, six hundred sixty-two thousand, sixteen".