28891131 has 8 divisors (see below), whose sum is σ = 38610240. Its totient is φ = 19216392.

The previous prime is 28891129. The next prime is 28891139. The reversal of 28891131 is 13119882.

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

It is not a de Polignac number, because 28891131 - 2¹ = 28891129 is a prime.

It is a super-2 number, since 2×28891131² = 1669394900918322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28891092 and 28891101.

It is not an unprimeable number, because it can be changed into a prime (28891139) 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, 9541 + ... + 12198.

It is an arithmetic number, because the mean of its divisors is an integer number (4826280).

Almost surely, 2^28891131 is an apocalyptic number.

28891131 is a deficient number, since it is larger than the sum of its proper divisors (9719109).

28891131 is a wasteful number, since it uses less digits than its factorization.

28891131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22185.

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

The square root of 28891131 is about 5375.0470695613. The cubic root of 28891131 is about 306.8467406224.

It can be divided in two parts, 288 and 91131, that added together give a palindrome (91419).

The spelling of 28891131 in words is "twenty-eight million, eight hundred ninety-one thousand, one hundred thirty-one".