1221823 has 2 divisors, whose sum is σ = 1221824. Its totient is φ = 1221822.

The previous prime is 1221821. The next prime is 1221853. The reversal of 1221823 is 3281221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221823 - 2¹ = 1221821 is a prime.

Together with 1221821, it forms a pair of twin primes.

1221823 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221823.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610911 + 610912.

It is an arithmetic number, because the mean of its divisors is an integer number (610912).

2^1221823 is an apocalyptic number.

1221823 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221823 is an equidigital number, since it uses as much as digits as its factorization.

1221823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 19.

The square root of 1221823 is about 1105.3610269953. The cubic root of 1221823 is about 106.9061686505.

The spelling of 1221823 in words is "one million, two hundred twenty-one thousand, eight hundred twenty-three".