21634228 has 24 divisors (see below), whose sum is σ = 47202624. Its totient is φ = 8428800.

The previous prime is 21634213. The next prime is 21634253. The reversal of 21634228 is 82243612.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 21634196 and 21634205.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34813 + ... + 35428.

It is an arithmetic number, because the mean of its divisors is an integer number (1966776).

Almost surely, 2^21634228 is an apocalyptic number.

21634228 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21634228 is an abundant number, since it is smaller than the sum of its proper divisors (25568396).

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

21634228 is a wasteful number, since it uses less digits than its factorization.

21634228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70263 (or 70261 counting only the distinct ones).

The product of its digits is 4608, while the sum is 28.

The square root of 21634228 is about 4651.2609043140. The cubic root of 21634228 is about 278.6423563672.

The spelling of 21634228 in words is "twenty-one million, six hundred thirty-four thousand, two hundred twenty-eight".