21627172 has 24 divisors (see below), whose sum is σ = 44311680. Its totient is φ = 9042240.

The previous prime is 21627169. The next prime is 21627173. The reversal of 21627172 is 27172612.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 21627172.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21627173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8272 + ... + 10567.

It is an arithmetic number, because the mean of its divisors is an integer number (1846320).

Almost surely, 2^21627172 is an apocalyptic number.

It is an amenable number.

21627172 is an abundant number, since it is smaller than the sum of its proper divisors (22684508).

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

21627172 is a wasteful number, since it uses less digits than its factorization.

21627172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18891 (or 18889 counting only the distinct ones).

The product of its digits is 2352, while the sum is 28.

The square root of 21627172 is about 4650.5023384576. The cubic root of 21627172 is about 278.6120600199.

Adding to 21627172 its reverse (27172612), we get a palindrome (48799784).

The spelling of 21627172 in words is "twenty-one million, six hundred twenty-seven thousand, one hundred seventy-two".