1216440 has 96 divisors (see below), whose sum is σ = 4118400. Its totient is φ = 311040.

The previous prime is 1216433. The next prime is 1216441. The reversal of 1216440 is 446121.

1216440 is a `hidden beast` number, since 1 + 21 + 644 + 0 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216441) 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 23 ways as a sum of consecutive naturals, for example, 11106 + ... + 11214.

It is an arithmetic number, because the mean of its divisors is an integer number (42900).

2^1216440 is an apocalyptic number.

1216440 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 1216440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2059200).

1216440 is an abundant number, since it is smaller than the sum of its proper divisors (2901960).

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

1216440 is a wasteful number, since it uses less digits than its factorization.

1216440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1216440 is about 1102.9233880918. The cubic root of 1216440 is about 106.7489382640.

It can be divided in two parts, 121 and 6440, that added together give a 8-th power (6561 = 3⁸).

The spelling of 1216440 in words is "one million, two hundred sixteen thousand, four hundred forty".