21242016 has 36 divisors (see below), whose sum is σ = 60407802. Its totient is φ = 7080576.

The previous prime is 21241991. The next prime is 21242047. The reversal of 21242016 is 61024212.

It can be written as a sum of positive squares in only one way, i.e., 20250000 + 992016 = 4500^2 + 996^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 21242016.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36591 + ... + 37166.

Almost surely, 2^21242016 is an apocalyptic number.

It is an amenable number.

21242016 is an abundant number, since it is smaller than the sum of its proper divisors (39165786).

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

21242016 is a wasteful number, since it uses less digits than its factorization.

21242016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73773 (or 73762 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21242016 is about 4608.9061609020. The cubic root of 21242016 is about 276.9482193696.

Adding to 21242016 its reverse (61024212), we get a palindrome (82266228).

The spelling of 21242016 in words is "twenty-one million, two hundred forty-two thousand, sixteen".