28180637 has 4 divisors (see below), whose sum is σ = 28192476. Its totient is φ = 28168800.

The previous prime is 28180631. The next prime is 28180657. The reversal of 28180637 is 73608182.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15832441 + 12348196 = 3979^2 + 3514^2 .

It is a cyclic number.

It is not a de Polignac number, because 28180637 - 2⁸ = 28180381 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28180597 and 28180606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28180631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 968 + ... + 7569.

It is an arithmetic number, because the mean of its divisors is an integer number (7048119).

Almost surely, 2^28180637 is an apocalyptic number.

It is an amenable number.

28180637 is a deficient number, since it is larger than the sum of its proper divisors (11839).

28180637 is an equidigital number, since it uses as much as digits as its factorization.

28180637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11838.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 28180637 is about 5308.5437739553. The cubic root of 28180637 is about 304.3104983439.

The spelling of 28180637 in words is "twenty-eight million, one hundred eighty thousand, six hundred thirty-seven".