28099640 has 96 divisors (see below), whose sum is σ = 70781040. Its totient is φ = 9999360.

The previous prime is 28099633. The next prime is 28099661. The reversal of 28099640 is 4699082.

It is a junction number, because it is equal to n+sod(n) for n = 28099594 and 28099603.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 653459 + ... + 653501.

Almost surely, 2^28099640 is an apocalyptic number.

28099640 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 28099640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35390520).

28099640 is an abundant number, since it is smaller than the sum of its proper divisors (42681400).

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

28099640 is a wasteful number, since it uses less digits than its factorization.

28099640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 28099640 is about 5300.9093559502. The cubic root of 28099640 is about 304.0186680595.

The spelling of 28099640 in words is "twenty-eight million, ninety-nine thousand, six hundred forty".