28278540 has 36 divisors (see below), whose sum is σ = 85778784. Its totient is φ = 7540896.

The previous prime is 28278533. The next prime is 28278559. The reversal of 28278540 is 4587282.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28278495 and 28278504.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78372 + ... + 78731.

It is an arithmetic number, because the mean of its divisors is an integer number (2382744).

Almost surely, 2^28278540 is an apocalyptic number.

28278540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28278540 is an abundant number, since it is smaller than the sum of its proper divisors (57500244).

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

28278540 is a wasteful number, since it uses less digits than its factorization.

28278540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157118 (or 157113 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 36.

The square root of 28278540 is about 5317.7570459734. The cubic root of 28278540 is about 304.6624950683.

The spelling of 28278540 in words is "twenty-eight million, two hundred seventy-eight thousand, five hundred forty".