1215120605 has 4 divisors (see below), whose sum is σ = 1458144732. Its totient is φ = 972096480.

The previous prime is 1215120593. The next prime is 1215120637. The reversal of 1215120605 is 5060215121.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 762367321 + 452753284 = 27611^2 + 21278^2 .

It is not a de Polignac number, because 1215120605 - 2⁸ = 1215120349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121512056 + ... + 121512065.

It is an arithmetic number, because the mean of its divisors is an integer number (364536183).

Almost surely, 2^1215120605 is an apocalyptic number.

It is an amenable number.

1215120605 is a deficient number, since it is larger than the sum of its proper divisors (243024127).

1215120605 is an equidigital number, since it uses as much as digits as its factorization.

1215120605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243024126.

The product of its (nonzero) digits is 600, while the sum is 23.

The square root of 1215120605 is about 34858.5800772206. The cubic root of 1215120605 is about 1067.1032971021.

Adding to 1215120605 its reverse (5060215121), we get a palindrome (6275335726).

The spelling of 1215120605 in words is "one billion, two hundred fifteen million, one hundred twenty thousand, six hundred five".