21384234 has 48 divisors (see below), whose sum is σ = 50369280. Its totient is φ = 6531840.

The previous prime is 21384229. The next prime is 21384241. The reversal of 21384234 is 43248312.

It is a junction number, because it is equal to n+sod(n) for n = 21384198 and 21384207.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9594 + ... + 11610.

It is an arithmetic number, because the mean of its divisors is an integer number (1049360).

Almost surely, 2^21384234 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21384234, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25184640).

21384234 is an abundant number, since it is smaller than the sum of its proper divisors (28985046).

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

21384234 is a wasteful number, since it uses less digits than its factorization.

21384234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2075 (or 2072 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

The square root of 21384234 is about 4624.3090294659. The cubic root of 21384234 is about 277.5649129857.

The spelling of 21384234 in words is "twenty-one million, three hundred eighty-four thousand, two hundred thirty-four".