661284 has 60 divisors (see below), whose sum is σ = 1873564. Its totient is φ = 202176.

The previous prime is 661267. The next prime is 661321. The reversal of 661284 is 482166.

It can be written as a sum of positive squares in 2 ways, for example, as 142884 + 518400 = 378^2 + 720^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

661284 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 19 ways as a sum of consecutive naturals, for example, 4134 + ... + 4290.

2⁶⁶¹²⁸⁴ 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 661284, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (936782).

661284 is an abundant number, since it is smaller than the sum of its proper divisors (1212280).

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

661284 is a wasteful number, since it uses less digits than its factorization.

661284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186 (or 175 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 661284 is about 813.1937038615. The cubic root of 661284 is about 87.1223012392.

The spelling of 661284 in words is "six hundred sixty-one thousand, two hundred eighty-four".