1215267205 has 4 divisors (see below), whose sum is σ = 1458320652. Its totient is φ = 972213760.

The previous prime is 1215267173. The next prime is 1215267223. The reversal of 1215267205 is 5027625121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5027625121 = 73 ⋅68871577.

It can be written as a sum of positive squares in 2 ways, for example, as 354079489 + 861187716 = 18817^2 + 29346^2 .

It is not a de Polignac number, because 1215267205 - 2⁵ = 1215267173 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 121526716 + ... + 121526725.

It is an arithmetic number, because the mean of its divisors is an integer number (364580163).

Almost surely, 2^1215267205 is an apocalyptic number.

It is an amenable number.

1215267205 is a deficient number, since it is larger than the sum of its proper divisors (243053447).

1215267205 is an equidigital number, since it uses as much as digits as its factorization.

1215267205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243053446.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 1215267205 is about 34860.6827959522. The cubic root of 1215267205 is about 1067.1462094549.

The spelling of 1215267205 in words is "one billion, two hundred fifteen million, two hundred sixty-seven thousand, two hundred five".