1220816 has 20 divisors (see below), whose sum is σ = 2424324. Its totient is φ = 595200.

The previous prime is 1220803. The next prime is 1220819. The reversal of 1220816 is 6180221.

It can be written as a sum of positive squares in 2 ways, for example, as 19600 + 1201216 = 140^2 + 1096^2 .

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220819) 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 3 ways as a sum of consecutive naturals, for example, 275 + ... + 1586.

2^1220816 is an apocalyptic number.

1220816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1220816 is a deficient number, since it is larger than the sum of its proper divisors (1203508).

1220816 is a wasteful number, since it uses less digits than its factorization.

1220816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1910 (or 1904 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 1220816 is about 1104.9054258171. The cubic root of 1220816 is about 106.8767906634.

The spelling of 1220816 in words is "one million, two hundred twenty thousand, eight hundred sixteen".