28221078 has 16 divisors (see below), whose sum is σ = 56526336. Its totient is φ = 9393000.

The previous prime is 28221077. The next prime is 28221097. The reversal of 28221078 is 87012282.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28221077) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1375 + ... + 7637.

It is an arithmetic number, because the mean of its divisors is an integer number (3532896).

Almost surely, 2^28221078 is an apocalyptic number.

28221078 is an abundant number, since it is smaller than the sum of its proper divisors (28305258).

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

28221078 is a wasteful number, since it uses less digits than its factorization.

28221078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7019.

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 28221078 is about 5312.3514567468. The cubic root of 28221078 is about 304.4559970496.

The spelling of 28221078 in words is "twenty-eight million, two hundred twenty-one thousand, seventy-eight".