21284452 has 24 divisors (see below), whose sum is σ = 42666624. Its totient is φ = 9100992.

The previous prime is 21284423. The next prime is 21284489. The reversal of 21284452 is 25448212.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 21284452.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23553 + ... + 24439.

It is an arithmetic number, because the mean of its divisors is an integer number (1777776).

Almost surely, 2^21284452 is an apocalyptic number.

It is an amenable number.

21284452 is an abundant number, since it is smaller than the sum of its proper divisors (21382172).

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

21284452 is a wasteful number, since it uses less digits than its factorization.

21284452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1755 (or 1753 counting only the distinct ones).

The product of its digits is 5120, while the sum is 28.

The square root of 21284452 is about 4613.5075593305. The cubic root of 21284452 is about 277.1325200989.

It can be divided in two parts, 21284 and 452, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21284452 in words is "twenty-one million, two hundred eighty-four thousand, four hundred fifty-two".