308728 has 32 divisors (see below), whose sum is σ = 684000. Its totient is φ = 127872.

The previous prime is 308723. The next prime is 308761. The reversal of 308728 is 827803.

308728 = 207² + 208² + ... + 213².

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 308696 and 308705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (308723) by changing a digit.

308728 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 7 ways as a sum of consecutive naturals, for example, 1998 + ... + 2146.

It is an arithmetic number, because the mean of its divisors is an integer number (21375).

2³⁰⁸⁷²⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 308728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (342000).

308728 is an abundant number, since it is smaller than the sum of its proper divisors (375272).

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

308728 is a wasteful number, since it uses less digits than its factorization.

308728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199 (or 195 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 308728 is about 555.6329723837. The cubic root of 308728 is about 67.5863002244.

308728 divided by its sum of digits (28) gives a triangular number (11026 = T₁₄₈).

It can be divided in two parts, 3087 and 28, that multiplied together give a square (86436 = 294²).

The spelling of 308728 in words is "three hundred eight thousand, seven hundred twenty-eight".