1212840 has 64 divisors (see below), whose sum is σ = 4046400. Its totient is φ = 323136.

The previous prime is 1212839. The next prime is 1212847. The reversal of 1212840 is 482121.

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

It is not an unprimeable number, because it can be changed into a prime (1212847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 519 + ... + 1641.

It is an arithmetic number, because the mean of its divisors is an integer number (63225).

2^1212840 is an apocalyptic number.

1212840 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 1212840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2023200).

1212840 is an abundant number, since it is smaller than the sum of its proper divisors (2833560).

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

1212840 is a wasteful number, since it uses less digits than its factorization.

1212840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1143 (or 1133 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 1212840 is about 1101.2901525030. The cubic root of 1212840 is about 106.6435279671.

Adding to 1212840 its reverse (482121), we get a palindrome (1694961).

The spelling of 1212840 in words is "one million, two hundred twelve thousand, eight hundred forty".