1243540 has 24 divisors (see below), whose sum is σ = 2642472. Its totient is φ = 491520.

The previous prime is 1243537. The next prime is 1243547. The reversal of 1243540 is 453421.

It can be written as a sum of positive squares in 4 ways, for example, as 318096 + 925444 = 564^2 + 962^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1243547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1620 + ... + 2260.

It is an arithmetic number, because the mean of its divisors is an integer number (110103).

2^1243540 is an apocalyptic number.

1243540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1243540 is an abundant number, since it is smaller than the sum of its proper divisors (1398932).

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

1243540 is a wasteful number, since it uses less digits than its factorization.

1243540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 747 (or 745 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 1243540 is about 1115.1412466589. The cubic root of 1243540 is about 107.5358452664.

Adding to 1243540 its reverse (453421), we get a palindrome (1696961).

The spelling of 1243540 in words is "one million, two hundred forty-three thousand, five hundred forty".