1220805 has 16 divisors (see below), whose sum is σ = 2170560. Its totient is φ = 651024.

The previous prime is 1220803. The next prime is 1220819. The reversal of 1220805 is 5080221.

It is not a de Polignac number, because 1220805 - 2¹ = 1220803 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4387 + ... + 4656.

It is an arithmetic number, because the mean of its divisors is an integer number (135660).

2^1220805 is an apocalyptic number.

1220805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1220805 is a deficient number, since it is larger than the sum of its proper divisors (949755).

1220805 is an equidigital number, since it uses as much as digits as its factorization.

1220805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9057 (or 9051 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 1220805 is about 1104.9004480043. The cubic root of 1220805 is about 106.8764696628.

It can be divided in two parts, 1220 and 805, that added together give a square (2025 = 45²).

The spelling of 1220805 in words is "one million, two hundred twenty thousand, eight hundred five".