1205640 has 96 divisors (see below), whose sum is σ = 4169880. Its totient is φ = 301056.

The previous prime is 1205639. The next prime is 1205647. The reversal of 1205640 is 465021.

It is a happy number.

1205640 is a `hidden beast` number, since 1 + 20 + 5 + 640 = 666.

1205640 is nontrivially palindromic in base 14.

It can be written as a sum of positive squares in 4 ways, for example, as 1205604 + 36 = 1098^2 + 6^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (1205647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6022 + ... + 6218.

2^1205640 is an apocalyptic number.

1205640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1205640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2084940).

1205640 is an abundant number, since it is smaller than the sum of its proper divisors (2964240).

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

1205640 is a wasteful number, since it uses less digits than its factorization.

1205640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 1205640 is about 1098.0163933202. The cubic root of 1205640 is about 106.4320799494.

The spelling of 1205640 in words is "one million, two hundred five thousand, six hundred forty".