1205323021 has 12 divisors (see below), whose sum is σ = 1409386332. Its totient is φ = 1027772928.

The previous prime is 1205322959. The next prime is 1205323039. The reversal of 1205323021 is 1203235021.

It can be written as a sum of positive squares in 2 ways, for example, as 893412100 + 311910921 = 29890^2 + 17661^2 .

It is not a de Polignac number, because 1205323021 - 2⁹ = 1205322509 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1205323021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205323321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54270 + ... + 73183.

It is an arithmetic number, because the mean of its divisors is an integer number (117448861).

Almost surely, 2^1205323021 is an apocalyptic number.

It is an amenable number.

1205323021 is a deficient number, since it is larger than the sum of its proper divisors (204063311).

1205323021 is a wasteful number, since it uses less digits than its factorization.

1205323021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127660 (or 127653 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 1205323021 is about 34717.7623270855. The cubic root of 1205323021 is about 1064.2275165587.

Adding to 1205323021 its reverse (1203235021), we get a palindrome (2408558042).

The spelling of 1205323021 in words is "one billion, two hundred five million, three hundred twenty-three thousand, twenty-one".