28128477 has 8 divisors (see below), whose sum is σ = 40389664. Its totient is φ = 17309808.

The previous prime is 28128469. The next prime is 28128487. The reversal of 28128477 is 77482182.

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

It is not a de Polignac number, because 28128477 - 2³ = 28128469 is a prime.

It is a super-2 number, since 2×28128477² = 1582422436679058, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 721243 = 28128477 / (2 + 8 + 1 + 2 + 8 + 4 + 7 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28128467) 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, 360583 + ... + 360660.

It is an arithmetic number, because the mean of its divisors is an integer number (5048708).

Almost surely, 2^28128477 is an apocalyptic number.

It is an amenable number.

28128477 is a deficient number, since it is larger than the sum of its proper divisors (12261187).

28128477 is a wasteful number, since it uses less digits than its factorization.

28128477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 721259.

The product of its digits is 50176, while the sum is 39.

The square root of 28128477 is about 5303.6286634718. The cubic root of 28128477 is about 304.1226313016.

The spelling of 28128477 in words is "twenty-eight million, one hundred twenty-eight thousand, four hundred seventy-seven".