28649940 has 96 divisors (see below), whose sum is σ = 88736256. Its totient is φ = 6848640.

The previous prime is 28649923. The next prime is 28650001. The reversal of 28649940 is 4994682.

It is a junction number, because it is equal to n+sod(n) for n = 28649892 and 28649901.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 54519 + ... + 55041.

It is an arithmetic number, because the mean of its divisors is an integer number (924336).

Almost surely, 2^28649940 is an apocalyptic number.

28649940 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 28649940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44368128).

28649940 is an abundant number, since it is smaller than the sum of its proper divisors (60086316).

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

28649940 is a wasteful number, since it uses less digits than its factorization.

28649940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 629 (or 627 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 28649940 is about 5352.5638716413. The cubic root of 28649940 is about 305.9904734528.

The spelling of 28649940 in words is "twenty-eight million, six hundred forty-nine thousand, nine hundred forty".