1240805 has 4 divisors (see below), whose sum is σ = 1488972. Its totient is φ = 992640.

The previous prime is 1240793. The next prime is 1240807. The reversal of 1240805 is 5080421.

1240805 = T₇₀₂ + T₇₀₃ + ... + T₇₀₆.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5080421 = 53 ⋅95857.

It can be written as a sum of positive squares in 2 ways, for example, as 872356 + 368449 = 934^2 + 607^2 .

It is not a de Polignac number, because 1240805 - 2⁶ = 1240741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1240807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124076 + ... + 124085.

It is an arithmetic number, because the mean of its divisors is an integer number (372243).

2^1240805 is an apocalyptic number.

It is an amenable number.

1240805 is a deficient number, since it is larger than the sum of its proper divisors (248167).

1240805 is an equidigital number, since it uses as much as digits as its factorization.

1240805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248166.

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 1240805 is about 1113.9142695917. The cubic root of 1240805 is about 107.4569504930.

The spelling of 1240805 in words is "one million, two hundred forty thousand, eight hundred five".