28072161 has 12 divisors (see below), whose sum is σ = 43667988. Its totient is φ = 17275104.

The previous prime is 28072157. The next prime is 28072169. The reversal of 28072161 is 16127082.

It can be written as a sum of positive squares in 2 ways, for example, as 13395600 + 14676561 = 3660^2 + 3831^2 .

It is not a de Polignac number, because 28072161 - 2² = 28072157 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28072169) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 119850 + ... + 120083.

It is an arithmetic number, because the mean of its divisors is an integer number (3638999).

Almost surely, 2^28072161 is an apocalyptic number.

It is an amenable number.

28072161 is a deficient number, since it is larger than the sum of its proper divisors (15595827).

28072161 is a wasteful number, since it uses less digits than its factorization.

28072161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239952 (or 239949 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 28072161 is about 5298.3168081948. The cubic root of 28072161 is about 303.9195344803.

The spelling of 28072161 in words is "twenty-eight million, seventy-two thousand, one hundred sixty-one".