21742384 has 40 divisors (see below), whose sum is σ = 45565040. Its totient is φ = 10015488.

The previous prime is 21742381. The next prime is 21742411. The reversal of 21742384 is 48324712.

It is not an unprimeable number, because it can be changed into a prime (21742381) by changing a digit.

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, 10282 + ... + 12214.

It is an arithmetic number, because the mean of its divisors is an integer number (1139126).

Almost surely, 2^21742384 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21742384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22782520).

21742384 is an abundant number, since it is smaller than the sum of its proper divisors (23822656).

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

21742384 is a wasteful number, since it uses less digits than its factorization.

21742384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1997 (or 1991 counting only the distinct ones).

The product of its digits is 10752, while the sum is 31.

The square root of 21742384 is about 4662.8729341469. The cubic root of 21742384 is about 279.1059236470.

The spelling of 21742384 in words is "twenty-one million, seven hundred forty-two thousand, three hundred eighty-four".