21628338 has 32 divisors (see below), whose sum is σ = 44478720. Its totient is φ = 7008720.

The previous prime is 21628283. The next prime is 21628339. The reversal of 21628338 is 83382612.

It is a junction number, because it is equal to n+sod(n) for n = 21628299 and 21628308.

It is not an unprimeable number, because it can be changed into a prime (21628339) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37593 + ... + 38163.

It is an arithmetic number, because the mean of its divisors is an integer number (1389960).

Almost surely, 2^21628338 is an apocalyptic number.

21628338 is an abundant number, since it is smaller than the sum of its proper divisors (22850382).

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

21628338 is a wasteful number, since it uses less digits than its factorization.

21628338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742.

The product of its digits is 13824, while the sum is 33.

The square root of 21628338 is about 4650.6276995692. The cubic root of 21628338 is about 278.6170669286.

The spelling of 21628338 in words is "twenty-one million, six hundred twenty-eight thousand, three hundred thirty-eight".