21220364 has 12 divisors (see below), whose sum is σ = 40511688. Its totient is φ = 9645600.

The previous prime is 21220357. The next prime is 21220379. The reversal of 21220364 is 46302212.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 241097 + ... + 241184.

It is an arithmetic number, because the mean of its divisors is an integer number (3375974).

Almost surely, 2^21220364 is an apocalyptic number.

It is an amenable number.

21220364 is a deficient number, since it is larger than the sum of its proper divisors (19291324).

21220364 is a wasteful number, since it uses less digits than its factorization.

21220364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 482296 (or 482294 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21220364 is about 4606.5566315850. The cubic root of 21220364 is about 276.8540895499.

Adding to 21220364 its reverse (46302212), we get a palindrome (67522576).

The spelling of 21220364 in words is "twenty-one million, two hundred twenty thousand, three hundred sixty-four".