28131516 has 96 divisors (see below), whose sum is σ = 84295680. Its totient is φ = 7947072.

The previous prime is 28131473. The next prime is 28131527. The reversal of 28131516 is 61513182.

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

It is a self number, because there is not a number n which added to its sum of digits gives 28131516.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 95866 + ... + 96158.

It is an arithmetic number, because the mean of its divisors is an integer number (878080).

Almost surely, 2^28131516 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28131516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42147840).

28131516 is an abundant number, since it is smaller than the sum of its proper divisors (56164164).

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

28131516 is a wasteful number, since it uses less digits than its factorization.

28131516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440 (or 432 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 28131516 is about 5303.9151576925. The cubic root of 28131516 is about 304.1335833745.

Adding to 28131516 its reverse (61513182), we get a palindrome (89644698).

The spelling of 28131516 in words is "twenty-eight million, one hundred thirty-one thousand, five hundred sixteen".