21245228 has 6 divisors (see below), whose sum is σ = 37179156. Its totient is φ = 10622612.

The previous prime is 21245227. The next prime is 21245281. The reversal of 21245228 is 82254212.

It is a junction number, because it is equal to n+sod(n) for n = 21245197 and 21245206.

It is not an unprimeable number, because it can be changed into a prime (21245221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2655650 + ... + 2655657.

It is an arithmetic number, because the mean of its divisors is an integer number (6196526).

Almost surely, 2^21245228 is an apocalyptic number.

It is an amenable number.

21245228 is a deficient number, since it is larger than the sum of its proper divisors (15933928).

21245228 is a wasteful number, since it uses less digits than its factorization.

21245228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5311311 (or 5311309 counting only the distinct ones).

The product of its digits is 2560, while the sum is 26.

The square root of 21245228 is about 4609.2546035124. The cubic root of 21245228 is about 276.9621777567.

The spelling of 21245228 in words is "twenty-one million, two hundred forty-five thousand, two hundred twenty-eight".