1215220309 has 16 divisors (see below), whose sum is σ = 1247961600. Its totient is φ = 1183029120.

The previous prime is 1215220301. The next prime is 1215220327. The reversal of 1215220309 is 9030225121.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1215220309 - 2³ = 1215220301 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 (1215220301) 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, 3311044 + ... + 3311410.

It is an arithmetic number, because the mean of its divisors is an integer number (77997600).

Almost surely, 2^1215220309 is an apocalyptic number.

It is an amenable number.

1215220309 is a deficient number, since it is larger than the sum of its proper divisors (32741291).

1215220309 is a wasteful number, since it uses less digits than its factorization.

1215220309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 900.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 1215220309 is about 34860.0101692469. The cubic root of 1215220309 is about 1067.1324825609.

The spelling of 1215220309 in words is "one billion, two hundred fifteen million, two hundred twenty thousand, three hundred nine".