21675384 has 64 divisors (see below), whose sum is σ = 62841600. Its totient is φ = 6909408.

The previous prime is 21675359. The next prime is 21675419. The reversal of 21675384 is 48357612.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2787 + ... + 7149.

It is an arithmetic number, because the mean of its divisors is an integer number (981900).

Almost surely, 2^21675384 is an apocalyptic number.

21675384 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21675384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31420800).

21675384 is an abundant number, since it is smaller than the sum of its proper divisors (41166216).

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

21675384 is a wasteful number, since it uses less digits than its factorization.

21675384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4401 (or 4391 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 21675384 is about 4655.6829788979. The cubic root of 21675384 is about 278.8189367463.

The spelling of 21675384 in words is "twenty-one million, six hundred seventy-five thousand, three hundred eighty-four".