28921816 has 64 divisors (see below), whose sum is σ = 69984000. Its totient is φ = 10872960.

The previous prime is 28921813. The next prime is 28921817. The reversal of 28921816 is 61812982.

It is a pancake number, because a pancake can be divided into 28921816 parts by 7605 straight cuts.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28921813) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17055 + ... + 18673.

It is an arithmetic number, because the mean of its divisors is an integer number (1093500).

Almost surely, 2^28921816 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 28921816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34992000).

28921816 is an abundant number, since it is smaller than the sum of its proper divisors (41062184).

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

28921816 is a wasteful number, since it uses less digits than its factorization.

28921816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1672 (or 1668 counting only the distinct ones).

The product of its digits is 13824, while the sum is 37.

The square root of 28921816 is about 5377.9007056657. The cubic root of 28921816 is about 306.9553352034.

The spelling of 28921816 in words is "twenty-eight million, nine hundred twenty-one thousand, eight hundred sixteen".