28440090 has 72 divisors (see below), whose sum is σ = 86030100. Its totient is φ = 6499584.

The previous prime is 28440053. The next prime is 28440103. The reversal of 28440090 is 9004482.

It can be written as a sum of positive squares in 2 ways, for example, as 26904969 + 1535121 = 5187^2 + 1239^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1186 + ... + 7634.

Almost surely, 2^28440090 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28440090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43015050).

28440090 is an abundant number, since it is smaller than the sum of its proper divisors (57590010).

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

28440090 is a wasteful number, since it uses less digits than its factorization.

28440090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6476 (or 6466 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 28440090 is about 5332.9250885419. The cubic root of 28440090 is about 305.2415536946.

The spelling of 28440090 in words is "twenty-eight million, four hundred forty thousand, ninety".