21741984 has 72 divisors (see below), whose sum is σ = 67459392. Its totient is φ = 6587520.

The previous prime is 21741983. The next prime is 21741989. The reversal of 21741984 is 48914712.

It is a tau number, because it is divible by the number of its divisors (72).

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 (21741983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 264 + ... + 6599.

It is an arithmetic number, because the mean of its divisors is an integer number (936936).

Almost surely, 2^21741984 is an apocalyptic number.

21741984 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 21741984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33729696).

21741984 is an abundant number, since it is smaller than the sum of its proper divisors (45717408).

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

21741984 is a wasteful number, since it uses less digits than its factorization.

21741984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6890 (or 6879 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 21741984 is about 4662.8300419381. The cubic root of 21741984 is about 279.1042120430.

The spelling of 21741984 in words is "twenty-one million, seven hundred forty-one thousand, nine hundred eighty-four".