21284180 has 48 divisors (see below), whose sum is σ = 47712000. Its totient is φ = 7952256.

The previous prime is 21284171. The next prime is 21284189. The reversal of 21284180 is 8148212.

It is an interprime number because it is at equal distance from previous prime (21284171) and next prime (21284189).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21284189) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29666 + ... + 30374.

It is an arithmetic number, because the mean of its divisors is an integer number (994000).

Almost surely, 2^21284180 is an apocalyptic number.

21284180 is a gapful number since it is divisible by the number (20) 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 21284180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23856000).

21284180 is an abundant number, since it is smaller than the sum of its proper divisors (26427820).

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

21284180 is a wasteful number, since it uses less digits than its factorization.

21284180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816 (or 814 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 21284180 is about 4613.4780805809. The cubic root of 21284180 is about 277.1313395757.

The spelling of 21284180 in words is "twenty-one million, two hundred eighty-four thousand, one hundred eighty".