28161756 has 72 divisors (see below), whose sum is σ = 84389760. Its totient is φ = 8044272.

The previous prime is 28161701. The next prime is 28161767. The reversal of 28161756 is 65716182.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 28161756.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4735 + ... + 8873.

It is an arithmetic number, because the mean of its divisors is an integer number (1172080).

Almost surely, 2^28161756 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 28161756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42194880).

28161756 is an abundant number, since it is smaller than the sum of its proper divisors (56228004).

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

28161756 is a wasteful number, since it uses less digits than its factorization.

28161756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4165 (or 4151 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 28161756 is about 5306.7651163397. The cubic root of 28161756 is about 304.2425205784.

The spelling of 28161756 in words is "twenty-eight million, one hundred sixty-one thousand, seven hundred fifty-six".