28910640 has 160 divisors (see below), whose sum is σ = 100279296. Its totient is φ = 6830080.

The previous prime is 28910639. The next prime is 28910641. The reversal of 28910640 is 4601982.

It is an interprime number because it is at equal distance from previous prime (28910639) and next prime (28910641).

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 = 28910598 and 28910607.

It is not an unprimeable number, because it can be changed into a prime (28910641) 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, 123964 + ... + 124196.

Almost surely, 2^28910640 is an apocalyptic number.

28910640 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 28910640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50139648).

28910640 is an abundant number, since it is smaller than the sum of its proper divisors (71368656).

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

28910640 is a wasteful number, since it uses less digits than its factorization.

28910640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307 (or 301 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 28910640 is about 5376.8615381094. The cubic root of 28910640 is about 306.9157921032.

The spelling of 28910640 in words is "twenty-eight million, nine hundred ten thousand, six hundred forty".