1216640 has 32 divisors (see below), whose sum is σ = 2910060. Its totient is φ = 486400.

The previous prime is 1216619. The next prime is 1216681. The reversal of 1216640 is 466121.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1098304 + 118336 = 1048^2 + 344^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 311 + ... + 1590.

2^1216640 is an apocalyptic number.

1216640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1216640 is an abundant number, since it is smaller than the sum of its proper divisors (1693420).

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

1216640 is an equidigital number, since it uses as much as digits as its factorization.

1216640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1920 (or 1908 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 1216640 is about 1103.0140524943. The cubic root of 1216640 is about 106.7547882902.

The spelling of 1216640 in words is "one million, two hundred sixteen thousand, six hundred forty".