28121772 has 24 divisors (see below), whose sum is σ = 74991616. Its totient is φ = 8034768.

The previous prime is 28121771. The next prime is 28121803. The reversal of 28121772 is 27712182.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (28121771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 167308 + ... + 167475.

Almost surely, 2^28121772 is an apocalyptic number.

It is an amenable number.

28121772 is an abundant number, since it is smaller than the sum of its proper divisors (46869844).

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

28121772 is a wasteful number, since it uses less digits than its factorization.

28121772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334797 (or 334795 counting only the distinct ones).

The product of its digits is 3136, while the sum is 30.

The square root of 28121772 is about 5302.9965114075. The cubic root of 28121772 is about 304.0984647569.

The spelling of 28121772 in words is "twenty-eight million, one hundred twenty-one thousand, seven hundred seventy-two".