28143531 has 48 divisors (see below), whose sum is σ = 46475520. Its totient is φ = 16912800.

The previous prime is 28143527. The next prime is 28143547. The reversal of 28143531 is 13534182.

It is a happy number.

It is not a de Polignac number, because 28143531 - 2² = 28143527 is a prime.

It is a super-2 number, since 2×28143531² = 1584116674295922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 28143495 and 28143504.

It is not an unprimeable number, because it can be changed into a prime (28143571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 186306 + ... + 186456.

It is an arithmetic number, because the mean of its divisors is an integer number (968240).

Almost surely, 2^28143531 is an apocalyptic number.

28143531 is a deficient number, since it is larger than the sum of its proper divisors (18331989).

28143531 is a wasteful number, since it uses less digits than its factorization.

28143531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238 (or 226 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 28143531 is about 5305.0476906433. The cubic root of 28143531 is about 304.1768758025.

The spelling of 28143531 in words is "twenty-eight million, one hundred forty-three thousand, five hundred thirty-one".