28645978 has 4 divisors (see below), whose sum is σ = 42968970. Its totient is φ = 14322988.

The previous prime is 28645937. The next prime is 28645979. The reversal of 28645978 is 87954682.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87954682 = 2 ⋅43977341.

It can be written as a sum of positive squares in only one way, i.e., 28483569 + 162409 = 5337^2 + 403^2 .

It is not an unprimeable number, because it can be changed into a prime (28645979) 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 as a sum of consecutive naturals, namely, 7161493 + ... + 7161496.

Almost surely, 2^28645978 is an apocalyptic number.

28645978 is a deficient number, since it is larger than the sum of its proper divisors (14322992).

28645978 is a wasteful number, since it uses less digits than its factorization.

28645978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14322991.

The product of its digits is 967680, while the sum is 49.

The square root of 28645978 is about 5352.1937558351. The cubic root of 28645978 is about 305.9763676624.

It can be divided in two parts, 286 and 45978, that added together give a palindrome (46264).

The spelling of 28645978 in words is "twenty-eight million, six hundred forty-five thousand, nine hundred seventy-eight".