661273161 has 16 divisors (see below), whose sum is σ = 928641024. Its totient is φ = 417735824.

The previous prime is 661273147. The next prime is 661273177. The reversal of 661273161 is 161372166.

661273161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 661273161 - 2¹³ = 661264969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661273141) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37401 + ... + 52166.

It is an arithmetic number, because the mean of its divisors is an integer number (58040064).

Almost surely, 2^661273161 is an apocalyptic number.

It is an amenable number.

661273161 is a deficient number, since it is larger than the sum of its proper divisors (267367863).

661273161 is a wasteful number, since it uses less digits than its factorization.

661273161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89700.

The product of its digits is 9072, while the sum is 33.

The square root of 661273161 is about 25715.2320813949. The cubic root of 661273161 is about 871.2182523406.

The spelling of 661273161 in words is "six hundred sixty-one million, two hundred seventy-three thousand, one hundred sixty-one".