21430784 has 40 divisors (see below), whose sum is σ = 45093840. Its totient is φ = 10146816.

The previous prime is 21430781. The next prime is 21430793. The reversal of 21430784 is 48703412.

It is not an unprimeable number, because it can be changed into a prime (21430781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8627 + ... + 10829.

It is an arithmetic number, because the mean of its divisors is an integer number (1127346).

Almost surely, 2^21430784 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 21430784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22546920).

21430784 is an abundant number, since it is smaller than the sum of its proper divisors (23663056).

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

21430784 is an equidigital number, since it uses as much as digits as its factorization.

21430784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2240 (or 2224 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 29.

The square root of 21430784 is about 4629.3394777225. The cubic root of 21430784 is about 277.7661715803.

The spelling of 21430784 in words is "twenty-one million, four hundred thirty thousand, seven hundred eighty-four".