21734784 has 128 divisors (see below), whose sum is σ = 67728000. Its totient is φ = 6842880.

The previous prime is 21734777. The next prime is 21734827. The reversal of 21734784 is 48743712.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

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, 65499 + ... + 65829.

It is an arithmetic number, because the mean of its divisors is an integer number (529125).

Almost surely, 2^21734784 is an apocalyptic number.

21734784 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 21734784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33864000).

21734784 is an abundant number, since it is smaller than the sum of its proper divisors (45993216).

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

21734784 is a wasteful number, since it uses less digits than its factorization.

21734784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 355 counting only the distinct ones).

The product of its digits is 37632, while the sum is 36.

The square root of 21734784 is about 4662.0579146982. The cubic root of 21734784 is about 279.0733995806.

The spelling of 21734784 in words is "twenty-one million, seven hundred thirty-four thousand, seven hundred eighty-four".