21228169 has 8 divisors (see below), whose sum is σ = 21584000. Its totient is φ = 20874672.

The previous prime is 21228167. The next prime is 21228209. The reversal of 21228169 is 96182212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21228169 - 2¹ = 21228167 is a prime.

It is a super-2 number, since 2×21228169² = 901270318185122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21228169.

It is not an unprimeable number, because it can be changed into a prime (21228167) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29587 + ... + 30295.

It is an arithmetic number, because the mean of its divisors is an integer number (2698000).

Almost surely, 2^21228169 is an apocalyptic number.

It is an amenable number.

21228169 is a deficient number, since it is larger than the sum of its proper divisors (355831).

21228169 is an equidigital number, since it uses as much as digits as its factorization.

21228169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1167.

The product of its digits is 3456, while the sum is 31.

The square root of 21228169 is about 4607.4037157601. The cubic root of 21228169 is about 276.8880283535. Note that the first 3 decimals are identical.

The spelling of 21228169 in words is "twenty-one million, two hundred twenty-eight thousand, one hundred sixty-nine".