647428 has 12 divisors (see below), whose sum is σ = 1199772. Its totient is φ = 304640.

The previous prime is 647417. The next prime is 647429. The reversal of 647428 is 824746.

It can be written as a sum of positive squares in 2 ways, for example, as 399424 + 248004 = 632^2 + 498^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 647428.

It is not an unprimeable number, because it can be changed into a prime (647429) by changing a digit.

647428 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 (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4693 + ... + 4828.

It is an arithmetic number, because the mean of its divisors is an integer number (99981).

2⁶⁴⁷⁴²⁸ is an apocalyptic number.

647428 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

647428 is a deficient number, since it is larger than the sum of its proper divisors (552344).

647428 is a wasteful number, since it uses less digits than its factorization.

647428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9542 (or 9540 counting only the distinct ones).

The product of its digits is 10752, while the sum is 31.

The square root of 647428 is about 804.6291071046. The cubic root of 647428 is about 86.5095047860.

The spelling of 647428 in words is "six hundred forty-seven thousand, four hundred twenty-eight".