28180001161 has 27 divisors (see below), whose sum is σ = 31451561631. Its totient is φ = 25236753984.

The previous prime is 28180001153. The next prime is 28180001177. The reversal of 28180001161 is 16110008182.

The square root of 28180001161 is 167869.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 5949191161 + 22230810000 = 77131^2 + 149100^2 .

It is not a de Polignac number, because 28180001161 - 2³ = 28180001153 is a prime.

It is a super-2 number, since 2×28180001161² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28180001111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 80744815 + ... + 80745163.

It is an arithmetic number, because the mean of its divisors is an integer number (1164872653).

Almost surely, 2^28180001161 is an apocalyptic number.

28180001161 is the 167869-th square number.

28180001161 is the 83935-th centered octagonal number.

It is an amenable number.

28180001161 is a deficient number, since it is larger than the sum of its proper divisors (3271560470).

28180001161 is an frugal number, since it uses more digits than its factorization.

28180001161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 798 (or 399 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 28.

The spelling of 28180001161 in words is "twenty-eight billion, one hundred eighty million, one thousand, one hundred sixty-one".