21628080 has 320 divisors, whose sum is σ = 85708800. Its totient is φ = 4976640.

The previous prime is 21628031. The next prime is 21628121. The reversal of 21628080 is 8082612.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 697665 + ... + 697695.

It is an arithmetic number, because the mean of its divisors is an integer number (267840).

Almost surely, 2^21628080 is an apocalyptic number.

21628080 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 21628080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42854400).

21628080 is an abundant number, since it is smaller than the sum of its proper divisors (64080720).

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

21628080 is a wasteful number, since it uses less digits than its factorization.

21628080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 21628080 is about 4650.5999612953. The cubic root of 21628080 is about 278.6159590689.

The spelling of 21628080 in words is "twenty-one million, six hundred twenty-eight thousand, eighty".