21532056 has 64 divisors (see below), whose sum is σ = 66259200. Its totient is φ = 5678208.

The previous prime is 21532051. The next prime is 21532067. The reversal of 21532056 is 65023512.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21532051) 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, 2746 + ... + 7113.

It is an arithmetic number, because the mean of its divisors is an integer number (1035300).

Almost surely, 2^21532056 is an apocalyptic number.

21532056 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21532056 is an abundant number, since it is smaller than the sum of its proper divisors (44727144).

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

21532056 is a wasteful number, since it uses less digits than its factorization.

21532056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9888 (or 9884 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 21532056 is about 4640.2646476252. The cubic root of 21532056 is about 278.2030157945.

Adding to 21532056 its reverse (65023512), we get a palindrome (86555568).

The spelling of 21532056 in words is "twenty-one million, five hundred thirty-two thousand, fifty-six".