400728 has 32 divisors (see below), whose sum is σ = 1022400. Its totient is φ = 130848.

The previous prime is 400723. The next prime is 400739. The reversal of 400728 is 827004.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400721) by changing a digit.

400728 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1275 + ... + 1557.

It is an arithmetic number, because the mean of its divisors is an integer number (31950).

2⁴⁰⁰⁷²⁸ 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 400728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (511200).

400728 is an abundant number, since it is smaller than the sum of its proper divisors (621672).

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

400728 is a wasteful number, since it uses less digits than its factorization.

400728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 351 (or 347 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 400728 is about 633.0308049376. The cubic root of 400728 is about 73.7253024646.

It can be divided in two parts, 400 and 728, that added together give a triangular number (1128 = T₄₇).

The spelling of 400728 in words is "four hundred thousand, seven hundred twenty-eight".