28719640 has 128 divisors (see below), whose sum is σ = 74649600. Its totient is φ = 9884160.

The previous prime is 28719631. The next prime is 28719661. The reversal of 28719640 is 4691782.

It is a self number, because there is not a number n which added to its sum of digits gives 28719640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 541854 + ... + 541906.

It is an arithmetic number, because the mean of its divisors is an integer number (583200).

Almost surely, 2^28719640 is an apocalyptic number.

28719640 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 28719640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37324800).

28719640 is an abundant number, since it is smaller than the sum of its proper divisors (45929960).

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

28719640 is a wasteful number, since it uses less digits than its factorization.

28719640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 28719640 is about 5359.0708149828. The cubic root of 28719640 is about 306.2384118897.

The spelling of 28719640 in words is "twenty-eight million, seven hundred nineteen thousand, six hundred forty".