21260656 has 20 divisors (see below), whose sum is σ = 41325232. Its totient is φ = 10596096.

The previous prime is 21260651. The next prime is 21260663. The reversal of 21260656 is 65606212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21260651) 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, 3421 + ... + 7363.

Almost surely, 2^21260656 is an apocalyptic number.

It is an amenable number.

21260656 is a deficient number, since it is larger than the sum of its proper divisors (20064576).

21260656 is a wasteful number, since it uses less digits than its factorization.

21260656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4288 (or 4282 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21260656 is about 4610.9278892648. The cubic root of 21260656 is about 277.0292036095.

Adding to 21260656 its reverse (65606212), we get a palindrome (86866868).

The spelling of 21260656 in words is "twenty-one million, two hundred sixty thousand, six hundred fifty-six".