28478665 has 8 divisors (see below), whose sum is σ = 34558920. Its totient is φ = 22526592.

The previous prime is 28478657. The next prime is 28478683. The reversal of 28478665 is 56687482.

It can be written as a sum of positive squares in 4 ways, for example, as 2702736 + 25775929 = 1644^2 + 5077^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28478665 - 2³ = 28478657 is a prime.

It is a super-2 number, since 2×28478665² = 1622068720364450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31554 + ... + 32443.

It is an arithmetic number, because the mean of its divisors is an integer number (4319865).

Almost surely, 2^28478665 is an apocalyptic number.

It is an amenable number.

28478665 is a deficient number, since it is larger than the sum of its proper divisors (6080255).

28478665 is an equidigital number, since it uses as much as digits as its factorization.

28478665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64091.

The product of its digits is 645120, while the sum is 46.

The square root of 28478665 is about 5336.5405460841. The cubic root of 28478665 is about 305.3794971559.

The spelling of 28478665 in words is "twenty-eight million, four hundred seventy-eight thousand, six hundred sixty-five".