28949640 has 128 divisors (see below), whose sum is σ = 96111360. Its totient is φ = 6938624.

The previous prime is 28949639. The next prime is 28949659. The reversal of 28949640 is 4694982.

It is a super-2 number, since 2×28949640² = 1676163312259200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28949592 and 28949601.

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, 46612 + ... + 47228.

It is an arithmetic number, because the mean of its divisors is an integer number (750870).

Almost surely, 2^28949640 is an apocalyptic number.

28949640 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 28949640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48055680).

28949640 is an abundant number, since it is smaller than the sum of its proper divisors (67161720).

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

28949640 is a wasteful number, since it uses less digits than its factorization.

28949640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671 (or 667 counting only the distinct ones).

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

The square root of 28949640 is about 5380.4869668089. The cubic root of 28949640 is about 307.0537382896.

The spelling of 28949640 in words is "twenty-eight million, nine hundred forty-nine thousand, six hundred forty".