1243440 has 120 divisors (see below), whose sum is σ = 4584528. Its totient is φ = 299520.

The previous prime is 1243439. The next prime is 1243471. The reversal of 1243440 is 443421.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×1243440² = 3092286067200, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7842 + ... + 7998.

2^1243440 is an apocalyptic number.

1243440 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 1243440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2292264).

1243440 is an abundant number, since it is smaller than the sum of its proper divisors (3341088).

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

1243440 is a wasteful number, since it uses less digits than its factorization.

1243440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 1243440 is about 1115.0964083881. The cubic root of 1243440 is about 107.5329626697.

Adding to 1243440 its reverse (443421), we get a palindrome (1686861).

The spelling of 1243440 in words is "one million, two hundred forty-three thousand, four hundred forty".