21828672 has 42 divisors (see below), whose sum is σ = 62569598. Its totient is φ = 7276032.

The previous prime is 21828671. The next prime is 21828673. The reversal of 21828672 is 27682812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21828671) and next prime (21828673).

It can be written as a sum of positive squares in only one way, i.e., 11943936 + 9884736 = 3456^2 + 3144^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21828671) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18373 + ... + 19524.

Almost surely, 2^21828672 is an apocalyptic number.

It is an amenable number.

21828672 is an abundant number, since it is smaller than the sum of its proper divisors (40740926).

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

21828672 is a wasteful number, since it uses less digits than its factorization.

21828672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37915 (or 37902 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 21828672 is about 4672.1164369052. The cubic root of 21828672 is about 279.4746612291.

It can be divided in two parts, 21828 and 672, that added together give a square (22500 = 150²).

The spelling of 21828672 in words is "twenty-one million, eight hundred twenty-eight thousand, six hundred seventy-two".