1278172161 has 48 divisors (see below), whose sum is σ = 2235018240. Its totient is φ = 687592800.

The previous prime is 1278172139. The next prime is 1278172163. The reversal of 1278172161 is 1612718721.

It is not a de Polignac number, because 1278172161 - 2¹³ = 1278163969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1278172163) 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 47 ways as a sum of consecutive naturals, for example, 191836 + ... + 198386.

It is an arithmetic number, because the mean of its divisors is an integer number (46562880).

Almost surely, 2^1278172161 is an apocalyptic number.

It is an amenable number.

1278172161 is a deficient number, since it is larger than the sum of its proper divisors (956846079).

1278172161 is a wasteful number, since it uses less digits than its factorization.

1278172161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6746 (or 6743 counting only the distinct ones).

The product of its digits is 9408, while the sum is 36.

The square root of 1278172161 is about 35751.5336873819. The cubic root of 1278172161 is about 1085.2499756027.

The spelling of 1278172161 in words is "one billion, two hundred seventy-eight million, one hundred seventy-two thousand, one hundred sixty-one".