21798234 has 40 divisors (see below), whose sum is σ = 49135680. Its totient is φ = 7222824.

The previous prime is 21798221. The next prime is 21798241. The reversal of 21798234 is 43289712.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 38437 + ... + 38999.

It is an arithmetic number, because the mean of its divisors is an integer number (1228392).

Almost surely, 2^21798234 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21798234, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24567840).

21798234 is an abundant number, since it is smaller than the sum of its proper divisors (27337446).

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

21798234 is a wasteful number, since it uses less digits than its factorization.

21798234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 816 (or 807 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21798234 is about 4668.8578903196. The cubic root of 21798234 is about 279.3447005562.

The spelling of 21798234 in words is "twenty-one million, seven hundred ninety-eight thousand, two hundred thirty-four".