21328086 has 32 divisors (see below), whose sum is σ = 47013120. Its totient is φ = 6408864.

The previous prime is 21328067. The next prime is 21328103. The reversal of 21328086 is 68082312.

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, 175 + ... + 6533.

It is an arithmetic number, because the mean of its divisors is an integer number (1469160).

Almost surely, 2^21328086 is an apocalyptic number.

21328086 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21328086, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23506560).

21328086 is an abundant number, since it is smaller than the sum of its proper divisors (25685034).

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

21328086 is a wasteful number, since it uses less digits than its factorization.

21328086 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6420.

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21328086 is about 4618.2340780866. The cubic root of 21328086 is about 277.3217685148.

The spelling of 21328086 in words is "twenty-one million, three hundred twenty-eight thousand, eighty-six".