1215546161 has 2 divisors, whose sum is σ = 1215546162. Its totient is φ = 1215546160.

The previous prime is 1215546133. The next prime is 1215546173. The reversal of 1215546161 is 1616455121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 897601600 + 317944561 = 29960^2 + 17831^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215546161 - 2⁶ = 1215546097 is a prime.

It is not a weakly prime, because it can be changed into another prime (1215546131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607773080 + 607773081.

It is an arithmetic number, because the mean of its divisors is an integer number (607773081).

Almost surely, 2^1215546161 is an apocalyptic number.

It is an amenable number.

1215546161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215546161 is an equidigital number, since it uses as much as digits as its factorization.

1215546161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7200, while the sum is 32.

The square root of 1215546161 is about 34864.6835780851. The cubic root of 1215546161 is about 1067.2278551656.

The spelling of 1215546161 in words is "one billion, two hundred fifteen million, five hundred forty-six thousand, one hundred sixty-one".