28226640 has 160 divisors (see below), whose sum is σ = 96243840. Its totient is φ = 6801408.

The previous prime is 28226633. The next prime is 28226641. The reversal of 28226640 is 4662282.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 28226598 and 28226607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28226641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 258906 + ... + 259014.

It is an arithmetic number, because the mean of its divisors is an integer number (601524).

Almost surely, 2^28226640 is an apocalyptic number.

28226640 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 28226640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48121920).

28226640 is an abundant number, since it is smaller than the sum of its proper divisors (68017200).

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

28226640 is a wasteful number, since it uses less digits than its factorization.

28226640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221 (or 215 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 28226640 is about 5312.8749279463. The cubic root of 28226640 is about 304.4759971481.

The spelling of 28226640 in words is "twenty-eight million, two hundred twenty-six thousand, six hundred forty".