1242640 has 60 divisors (see below), whose sum is σ = 3371436. Its totient is φ = 424704.

The previous prime is 1242629. The next prime is 1242641. The reversal of 1242640 is 462421.

It can be written as a sum of positive squares in 2 ways, for example, as 226576 + 1016064 = 476^2 + 1008^2 .

It is not an unprimeable number, because it can be changed into a prime (1242641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3762 + ... + 4078.

2^1242640 is an apocalyptic number.

1242640 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 1242640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1685718).

1242640 is an abundant number, since it is smaller than the sum of its proper divisors (2128796).

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

1242640 is a wasteful number, since it uses less digits than its factorization.

1242640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344 (or 331 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 1242640 is about 1114.7376372941. The cubic root of 1242640 is about 107.5098963307.

The spelling of 1242640 in words is "one million, two hundred forty-two thousand, six hundred forty".