28918131 has 8 divisors (see below), whose sum is σ = 42062784. Its totient is φ = 17526120.

The previous prime is 28918129. The next prime is 28918159. The reversal of 28918131 is 13181982.

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

It is not a de Polignac number, because 28918131 - 2¹ = 28918129 is a prime.

It is a super-2 number, since 2×28918131² = 1672516601066322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 876307 = 28918131 / (2 + 8 + 9 + 1 + 8 + 1 + 3 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 28918092 and 28918101.

It is not an unprimeable number, because it can be changed into a prime (28918121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 438121 + ... + 438186.

It is an arithmetic number, because the mean of its divisors is an integer number (5257848).

Almost surely, 2^28918131 is an apocalyptic number.

28918131 is a deficient number, since it is larger than the sum of its proper divisors (13144653).

28918131 is a wasteful number, since it uses less digits than its factorization.

28918131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 876321.

The product of its digits is 3456, while the sum is 33.

The square root of 28918131 is about 5377.5580889471. The cubic root of 28918131 is about 306.9422980039.

The spelling of 28918131 in words is "twenty-eight million, nine hundred eighteen thousand, one hundred thirty-one".