1221254161 has 6 divisors (see below), whose sum is σ = 1276661330. Its totient is φ = 1168155648.

The previous prime is 1221254159. The next prime is 1221254189. The reversal of 1221254161 is 1614521221.

It can be written as a sum of positive squares in only one way, i.e., 1185493761 + 35760400 = 34431^2 + 5980^2 .

It is not a de Polignac number, because 1221254161 - 2¹ = 1221254159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221254101) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 1153776 + ... + 1154833.

Almost surely, 2^1221254161 is an apocalyptic number.

It is an amenable number.

1221254161 is a deficient number, since it is larger than the sum of its proper divisors (55407169).

1221254161 is an equidigital number, since it uses as much as digits as its factorization.

1221254161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2308655 (or 2308632 counting only the distinct ones).

The product of its digits is 960, while the sum is 25.

The square root of 1221254161 is about 34946.4470440129. The cubic root of 1221254161 is about 1068.8957545659.

Adding to 1221254161 its reverse (1614521221), we get a palindrome (2835775382).

The spelling of 1221254161 in words is "one billion, two hundred twenty-one million, two hundred fifty-four thousand, one hundred sixty-one".