28131872 has 24 divisors (see below), whose sum is σ = 58643676. Its totient is φ = 13238272.

The previous prime is 28131871. The next prime is 28131881. The reversal of 28131872 is 27813182.

It can be written as a sum of positive squares in 2 ways, for example, as 26584336 + 1547536 = 5156^2 + 1244^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (28131871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25313 + ... + 26400.

Almost surely, 2^28131872 is an apocalyptic number.

It is an amenable number.

28131872 is an abundant number, since it is smaller than the sum of its proper divisors (30511804).

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

28131872 is a wasteful number, since it uses less digits than its factorization.

28131872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51740 (or 51732 counting only the distinct ones).

The product of its digits is 5376, while the sum is 32.

The square root of 28131872 is about 5303.9487177008. The cubic root of 28131872 is about 304.1348662903.

The spelling of 28131872 in words is "twenty-eight million, one hundred thirty-one thousand, eight hundred seventy-two".