28177945 has 4 divisors (see below), whose sum is σ = 33813540. Its totient is φ = 22542352.

The previous prime is 28177939. The next prime is 28177949. The reversal of 28177945 is 54977182.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14197824 + 13980121 = 3768^2 + 3739^2 .

It is a cyclic number.

It is not a de Polignac number, because 28177945 - 2¹⁷ = 28046873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28177949) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2817790 + ... + 2817799.

It is an arithmetic number, because the mean of its divisors is an integer number (8453385).

Almost surely, 2^28177945 is an apocalyptic number.

It is an amenable number.

28177945 is a deficient number, since it is larger than the sum of its proper divisors (5635595).

28177945 is an equidigital number, since it uses as much as digits as its factorization.

28177945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5635594.

The product of its digits is 141120, while the sum is 43.

The square root of 28177945 is about 5308.2902143722. The cubic root of 28177945 is about 304.3008081212.

The spelling of 28177945 in words is "twenty-eight million, one hundred seventy-seven thousand, nine hundred forty-five".