1021213309 has 4 divisors (see below), whose sum is σ = 1021279680. Its totient is φ = 1021146940.

The previous prime is 1021213289. The next prime is 1021213313. The reversal of 1021213309 is 9033121201.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9033121201 = 13 ⋅694855477.

It is a cyclic number.

It is not a de Polignac number, because 1021213309 - 2¹³ = 1021205117 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 1021213309.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021213399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3174 + ... + 45304.

It is an arithmetic number, because the mean of its divisors is an integer number (255319920).

Almost surely, 2^1021213309 is an apocalyptic number.

It is an amenable number.

1021213309 is a deficient number, since it is larger than the sum of its proper divisors (66371).

1021213309 is an equidigital number, since it uses as much as digits as its factorization.

1021213309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66370.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 1021213309 is about 31956.4282891565. The cubic root of 1021213309 is about 1007.0216835608.

The spelling of 1021213309 in words is "one billion, twenty-one million, two hundred thirteen thousand, three hundred nine".