661028 has 12 divisors (see below), whose sum is σ = 1224972. Its totient is φ = 311040.

The previous prime is 661027. The next prime is 661049. The reversal of 661028 is 820166.

It can be written as a sum of positive squares in 2 ways, for example, as 222784 + 438244 = 472^2 + 662^2 .

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 660994 and 661012.

It is not an unprimeable number, because it can be changed into a prime (661027) by changing a digit.

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, 4793 + ... + 4928.

It is an arithmetic number, because the mean of its divisors is an integer number (102081).

2⁶⁶¹⁰²⁸ is an apocalyptic number.

661028 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

661028 is a deficient number, since it is larger than the sum of its proper divisors (563944).

661028 is a wasteful number, since it uses less digits than its factorization.

661028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9742 (or 9740 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 661028 is about 813.0362845532. The cubic root of 661028 is about 87.1110573623. Note that the first 3 decimals are identical.

The spelling of 661028 in words is "six hundred sixty-one thousand, twenty-eight".