21360656 has 20 divisors (see below), whose sum is σ = 41630892. Its totient is φ = 10617216.

The previous prime is 21360649. The next prime is 21360659. The reversal of 21360656 is 65606312.

It can be written as a sum of positive squares in 2 ways, for example, as 15523600 + 5837056 = 3940^2 + 2416^2 .

It is not an unprimeable number, because it can be changed into a prime (21360659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1091 + ... + 6626.

Almost surely, 2^21360656 is an apocalyptic number.

It is an amenable number.

21360656 is a deficient number, since it is larger than the sum of its proper divisors (20270236).

21360656 is a wasteful number, since it uses less digits than its factorization.

21360656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7898 (or 7892 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 21360656 is about 4621.7589725125. The cubic root of 21360656 is about 277.4628622216.

Adding to 21360656 its reverse (65606312), we get a palindrome (86966968).

The spelling of 21360656 in words is "twenty-one million, three hundred sixty thousand, six hundred fifty-six".