1215205072161 has 4 divisors (see below), whose sum is σ = 1620273429552. Its totient is φ = 810136714772.

The previous prime is 1215205072121. The next prime is 1215205072163. The reversal of 1215205072161 is 1612705025121.

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.

It is a cyclic number.

It is not a de Polignac number, because 1215205072161 - 2⁶ = 1215205072097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1215205072163) 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, 202534178691 + ... + 202534178696.

It is an arithmetic number, because the mean of its divisors is an integer number (405068357388).

Almost surely, 2^{1215205072161} is an apocalyptic number.

It is an amenable number.

1215205072161 is a deficient number, since it is larger than the sum of its proper divisors (405068357391).

1215205072161 is an equidigital number, since it uses as much as digits as its factorization.

1215205072161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405068357390.

The product of its (nonzero) digits is 8400, while the sum is 33.

The spelling of 1215205072161 in words is "one trillion, two hundred fifteen billion, two hundred five million, seventy-two thousand, one hundred sixty-one".