21236628 has 24 divisors (see below), whose sum is σ = 56631232. Its totient is φ = 6067584.

The previous prime is 21236627. The next prime is 21236651. The reversal of 21236628 is 82663212.

It is a junction number, because it is equal to n+sod(n) for n = 21236595 and 21236604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236627) 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, 126325 + ... + 126492.

Almost surely, 2^21236628 is an apocalyptic number.

21236628 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21236628 is an abundant number, since it is smaller than the sum of its proper divisors (35394604).

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

21236628 is a wasteful number, since it uses less digits than its factorization.

21236628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252831 (or 252829 counting only the distinct ones).

The product of its digits is 6912, while the sum is 30.

The square root of 21236628 is about 4608.3216033606. The cubic root of 21236628 is about 276.9248015800.

The spelling of 21236628 in words is "twenty-one million, two hundred thirty-six thousand, six hundred twenty-eight".