1221843 has 16 divisors (see below), whose sum is σ = 1886976. Its totient is φ = 688800.

The previous prime is 1221823. The next prime is 1221853. The reversal of 1221843 is 3481221.

It is not a de Polignac number, because 1221843 - 2⁵ = 1221811 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

1221843 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221823) 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, 1393 + ... + 2093.

It is an arithmetic number, because the mean of its divisors is an integer number (117936).

2^1221843 is an apocalyptic number.

1221843 is a deficient number, since it is larger than the sum of its proper divisors (665133).

1221843 is an equidigital number, since it uses as much as digits as its factorization.

1221843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794.

The product of its digits is 384, while the sum is 21.

The square root of 1221843 is about 1105.3700737762. The cubic root of 1221843 is about 106.9067519624.

The spelling of 1221843 in words is "one million, two hundred twenty-one thousand, eight hundred forty-three".