21189084 has 48 divisors (see below), whose sum is σ = 56840448. Its totient is φ = 6018048.

The previous prime is 21189079. The next prime is 21189101. The reversal of 21189084 is 48098112.

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, 15559 + ... + 16865.

It is an arithmetic number, because the mean of its divisors is an integer number (1184176).

Almost surely, 2^21189084 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 21189084, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28420224).

21189084 is an abundant number, since it is smaller than the sum of its proper divisors (35651364).

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

21189084 is a wasteful number, since it uses less digits than its factorization.

21189084 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1514 (or 1512 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 21189084 is about 4603.1602188062. The cubic root of 21189084 is about 276.7179898658.

The spelling of 21189084 in words is "twenty-one million, one hundred eighty-nine thousand, eighty-four".