28121916 has 24 divisors (see below), whose sum is σ = 68471424. Its totient is φ = 8966320.

The previous prime is 28121897. The next prime is 28121963. The reversal of 28121916 is 61912182.

It is a happy number.

It is a super-2 number, since 2×28121916² = 1581684319022112, which contains 22 as substring.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50670 + ... + 51221.

It is an arithmetic number, because the mean of its divisors is an integer number (2852976).

Almost surely, 2^28121916 is an apocalyptic number.

It is an amenable number.

28121916 is an abundant number, since it is smaller than the sum of its proper divisors (40349508).

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

28121916 is a wasteful number, since it uses less digits than its factorization.

28121916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101921 (or 101919 counting only the distinct ones).

The product of its digits is 1728, while the sum is 30.

The square root of 28121916 is about 5303.0100886195. The cubic root of 28121916 is about 304.0989838103.

The spelling of 28121916 in words is "twenty-eight million, one hundred twenty-one thousand, nine hundred sixteen".