28689388 has 48 divisors (see below), whose sum is σ = 62233920. Its totient is φ = 11268864.

The previous prime is 28689379. The next prime is 28689391. The reversal of 28689388 is 88398682.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 97770 + ... + 98062.

It is an arithmetic number, because the mean of its divisors is an integer number (1296540).

Almost surely, 2^28689388 is an apocalyptic number.

28689388 is a gapful number since it is divisible by the number (28) 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 28689388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31116960).

28689388 is an abundant number, since it is smaller than the sum of its proper divisors (33544532).

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

28689388 is a wasteful number, since it uses less digits than its factorization.

28689388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586 (or 584 counting only the distinct ones).

The product of its digits is 1327104, while the sum is 52.

The square root of 28689388 is about 5356.2475670940. The cubic root of 28689388 is about 306.1308481085.

The spelling of 28689388 in words is "twenty-eight million, six hundred eighty-nine thousand, three hundred eighty-eight".