21072084 has 48 divisors (see below), whose sum is σ = 54538176. Its totient is φ = 6278400.

The previous prime is 21072053. The next prime is 21072101. The reversal of 21072084 is 48027012.

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, 6744 + ... + 9360.

It is an arithmetic number, because the mean of its divisors is an integer number (1136212).

Almost surely, 2^21072084 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 21072084, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27269088).

21072084 is an abundant number, since it is smaller than the sum of its proper divisors (33466092).

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

21072084 is a wasteful number, since it uses less digits than its factorization.

21072084 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2696 (or 2694 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 21072084 is about 4590.4339664132. The cubic root of 21072084 is about 276.2077306115.

Adding to 21072084 its reverse (48027012), we get a palindrome (69099096).

The spelling of 21072084 in words is "twenty-one million, seventy-two thousand, eighty-four".