21625056 has 108 divisors (see below), whose sum is σ = 64478232. Its totient is φ = 7138368.

The previous prime is 21625033. The next prime is 21625061. The reversal of 21625056 is 65052612.

It is a tau number, because it is divible by the number of its divisors (108).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 209901 + ... + 210003.

Almost surely, 2^21625056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21625056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32239116).

21625056 is an abundant number, since it is smaller than the sum of its proper divisors (42853176).

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

21625056 is an frugal number, since it uses more digits than its factorization.

21625056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 21625056 is about 4650.2748305880. The cubic root of 21625056 is about 278.6029732664.

Adding to 21625056 its reverse (65052612), we get a palindrome (86677668).

The spelling of 21625056 in words is "twenty-one million, six hundred twenty-five thousand, fifty-six".