1229821 has 4 divisors (see below), whose sum is σ = 1250044. Its totient is φ = 1209600.

The previous prime is 1229807. The next prime is 1229827. The reversal of 1229821 is 1289221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1289221 = 1049 ⋅1229.

It can be written as a sum of positive squares in 2 ways, for example, as 348100 + 881721 = 590^2 + 939^2 .

It is a cyclic number.

It is not a de Polignac number, because 1229821 - 2⁹ = 1229309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1229827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10020 + ... + 10141.

It is an arithmetic number, because the mean of its divisors is an integer number (312511).

2^1229821 is an apocalyptic number.

It is an amenable number.

1229821 is a deficient number, since it is larger than the sum of its proper divisors (20223).

1229821 is an equidigital number, since it uses as much as digits as its factorization.

1229821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20222.

The product of its digits is 576, while the sum is 25.

The square root of 1229821 is about 1108.9729482724. The cubic root of 1229821 is about 107.1389292105.

The spelling of 1229821 in words is "one million, two hundred twenty-nine thousand, eight hundred twenty-one".