28111540 has 48 divisors (see below), whose sum is σ = 63277200. Its totient is φ = 10452992.

The previous prime is 28111537. The next prime is 28111541. The reversal of 28111540 is 4511182.

It can be written as a sum of positive squares in 8 ways, for example, as 4511376 + 23600164 = 2124^2 + 4858^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28111541) 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, 29796 + ... + 30724.

It is an arithmetic number, because the mean of its divisors is an integer number (1318275).

Almost surely, 2^28111540 is an apocalyptic number.

28111540 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 28111540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31638600).

28111540 is an abundant number, since it is smaller than the sum of its proper divisors (35165660).

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

28111540 is a wasteful number, since it uses less digits than its factorization.

28111540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1044 (or 1042 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 28111540 is about 5302.0316860615. The cubic root of 28111540 is about 304.0615785922.

The spelling of 28111540 in words is "twenty-eight million, one hundred eleven thousand, five hundred forty".