28215121 has 8 divisors (see below), whose sum is σ = 32590944. Its totient is φ = 24141120.

The previous prime is 28215119. The next prime is 28215139. The reversal of 28215121 is 12151282.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28215121 - 2¹ = 28215119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28215092 and 28215101.

It is not an unprimeable number, because it can be changed into a prime (28215101) 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, 75255 + ... + 75628.

It is an arithmetic number, because the mean of its divisors is an integer number (4073868).

Almost surely, 2^28215121 is an apocalyptic number.

It is an amenable number.

28215121 is a deficient number, since it is larger than the sum of its proper divisors (4375823).

28215121 is a wasteful number, since it uses less digits than its factorization.

28215121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150911.

The product of its digits is 320, while the sum is 22.

The square root of 28215121 is about 5311.7907526558. The cubic root of 28215121 is about 304.4345736771.

The spelling of 28215121 in words is "twenty-eight million, two hundred fifteen thousand, one hundred twenty-one".