21627220 has 12 divisors (see below), whose sum is σ = 45417204. Its totient is φ = 8650880.

The previous prime is 21627197. The next prime is 21627223. The reversal of 21627220 is 2272612.

It can be written as a sum of positive squares in 2 ways, for example, as 2808976 + 18818244 = 1676^2 + 4338^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21627191 and 21627200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21627223) 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, 540661 + ... + 540700.

It is an arithmetic number, because the mean of its divisors is an integer number (3784767).

Almost surely, 2^21627220 is an apocalyptic number.

21627220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21627220 is an abundant number, since it is smaller than the sum of its proper divisors (23789984).

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

21627220 is a wasteful number, since it uses less digits than its factorization.

21627220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1081370 (or 1081368 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21627220 is about 4650.5074991876. The cubic root of 21627220 is about 278.6122661398.

Adding to 21627220 its reverse (2272612), we get a palindrome (23899832).

The spelling of 21627220 in words is "twenty-one million, six hundred twenty-seven thousand, two hundred twenty".