21352656 has 80 divisors (see below), whose sum is σ = 62565440. Its totient is φ = 6220800.

The previous prime is 21352651. The next prime is 21352687. The reversal of 21352656 is 65625312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21352651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10956 + ... + 12756.

It is an arithmetic number, because the mean of its divisors is an integer number (782068).

Almost surely, 2^21352656 is an apocalyptic number.

21352656 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21352656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31282720).

21352656 is an abundant number, since it is smaller than the sum of its proper divisors (41212784).

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

21352656 is a wasteful number, since it uses less digits than its factorization.

21352656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1844 (or 1838 counting only the distinct ones).

The product of its digits is 10800, while the sum is 30.

The square root of 21352656 is about 4620.8934201083. The cubic root of 21352656 is about 277.4282194019.

Adding to 21352656 its reverse (65625312), we get a palindrome (86977968).

The spelling of 21352656 in words is "twenty-one million, three hundred fifty-two thousand, six hundred fifty-six".