21500628 has 48 divisors (see below), whose sum is σ = 53202240. Its totient is φ = 6739200.

The previous prime is 21500627. The next prime is 21500641. The reversal of 21500628 is 82600512.

It is a junction number, because it is equal to n+sod(n) for n = 21500598 and 21500607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500621) 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, 41008 + ... + 41528.

It is an arithmetic number, because the mean of its divisors is an integer number (1108380).

Almost surely, 2^21500628 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 21500628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26601120).

21500628 is an abundant number, since it is smaller than the sum of its proper divisors (31701612).

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

21500628 is a wasteful number, since it uses less digits than its factorization.

21500628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728 (or 726 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 21500628 is about 4636.8769662349. The cubic root of 21500628 is about 278.0675956602.

The spelling of 21500628 in words is "twenty-one million, five hundred thousand, six hundred twenty-eight".