21220616 has 32 divisors (see below), whose sum is σ = 42094080. Its totient is φ = 10012800.

The previous prime is 21220613. The next prime is 21220627. The reversal of 21220616 is 61602212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21220613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9125 + ... + 11211.

It is an arithmetic number, because the mean of its divisors is an integer number (1315440).

Almost surely, 2^21220616 is an apocalyptic number.

It is an amenable number.

21220616 is a deficient number, since it is larger than the sum of its proper divisors (20873464).

21220616 is a wasteful number, since it uses less digits than its factorization.

21220616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2165 (or 2161 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21220616 is about 4606.5839838214. The cubic root of 21220616 is about 276.8551854619.

Adding to 21220616 its reverse (61602212), we get a palindrome (82822828).

The spelling of 21220616 in words is "twenty-one million, two hundred twenty thousand, six hundred sixteen".