1209640 has 16 divisors (see below), whose sum is σ = 2721780. Its totient is φ = 483840.

The previous prime is 1209631. The next prime is 1209647. The reversal of 1209640 is 469021.

It can be written as a sum of positive squares in 2 ways, for example, as 1127844 + 81796 = 1062^2 + 286^2 .

It is not an unprimeable number, because it can be changed into a prime (1209647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15081 + ... + 15160.

2^1209640 is an apocalyptic number.

1209640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1209640 is an abundant number, since it is smaller than the sum of its proper divisors (1512140).

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

1209640 is a wasteful number, since it uses less digits than its factorization.

1209640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30252 (or 30248 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 1209640 is about 1099.8363514633. The cubic root of 1209640 is about 106.5496546724.

It can be divided in two parts, 1209 and 640, that added together give a square (1849 = 43²).

The spelling of 1209640 in words is "one million, two hundred nine thousand, six hundred forty".