21067220 has 12 divisors (see below), whose sum is σ = 44241204. Its totient is φ = 8426880.

The previous prime is 21067213. The next prime is 21067229. The reversal of 21067220 is 2276012.

It can be written as a sum of positive squares in 2 ways, for example, as 12517444 + 8549776 = 3538^2 + 2924^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1053361 = 21067220 / (2 + 1 + 0 + 6 + 7 + 2 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 21067192 and 21067201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21067229) 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, 526661 + ... + 526700.

It is an arithmetic number, because the mean of its divisors is an integer number (3686767).

Almost surely, 2^21067220 is an apocalyptic number.

21067220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21067220 is an abundant number, since it is smaller than the sum of its proper divisors (23173984).

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

21067220 is a wasteful number, since it uses less digits than its factorization.

21067220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1053370 (or 1053368 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21067220 is about 4589.9041384325. The cubic root of 21067220 is about 276.1864769347.

The spelling of 21067220 in words is "twenty-one million, sixty-seven thousand, two hundred twenty".