28122978 has 16 divisors (see below), whose sum is σ = 60572736. Its totient is φ = 8653200.

The previous prime is 28122977. The next prime is 28123057. The reversal of 28122978 is 87922182.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (28122971) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180198 + ... + 180353.

It is an arithmetic number, because the mean of its divisors is an integer number (3785796).

Almost surely, 2^28122978 is an apocalyptic number.

28122978 is an abundant number, since it is smaller than the sum of its proper divisors (32449758).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28122978 is a wasteful number, since it uses less digits than its factorization.

28122978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360569.

The product of its digits is 32256, while the sum is 39.

The square root of 28122978 is about 5303.1102194844. The cubic root of 28122978 is about 304.1028117744.

The spelling of 28122978 in words is "twenty-eight million, one hundred twenty-two thousand, nine hundred seventy-eight".