28640131 has 4 divisors (see below), whose sum is σ = 30843232. Its totient is φ = 26437032.

The previous prime is 28640119. The next prime is 28640147. The reversal of 28640131 is 13104682.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13104682 = 2 ⋅6552341.

It is a cyclic number.

It is not a de Polignac number, because 28640131 - 2¹¹ = 28638083 is a prime.

It is a super-2 number, since 2×28640131² = 1640514207394322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28640096 and 28640105.

It is not an unprimeable number, because it can be changed into a prime (28640191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1101531 + ... + 1101556.

It is an arithmetic number, because the mean of its divisors is an integer number (7710808).

Almost surely, 2^28640131 is an apocalyptic number.

28640131 is a deficient number, since it is larger than the sum of its proper divisors (2203101).

28640131 is a wasteful number, since it uses less digits than its factorization.

28640131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2203100.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 28640131 is about 5351.6475033395. The cubic root of 28640131 is about 305.9555483866.

The spelling of 28640131 in words is "twenty-eight million, six hundred forty thousand, one hundred thirty-one".