28185121 has 2 divisors, whose sum is σ = 28185122. Its totient is φ = 28185120.

The previous prime is 28185119. The next prime is 28185137. The reversal of 28185121 is 12158182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27973521 + 211600 = 5289^2 + 460^2 .

It is a cyclic number.

It is not a de Polignac number, because 28185121 - 2¹ = 28185119 is a prime.

Together with 28185119, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 28185121.

It is not a weakly prime, because it can be changed into another prime (28185181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14092560 + 14092561.

It is an arithmetic number, because the mean of its divisors is an integer number (14092561).

Almost surely, 2^28185121 is an apocalyptic number.

It is an amenable number.

28185121 is a deficient number, since it is larger than the sum of its proper divisors (1).

28185121 is an equidigital number, since it uses as much as digits as its factorization.

28185121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1280, while the sum is 28.

The square root of 28185121 is about 5308.9660952016. The cubic root of 28185121 is about 304.3266377462.

The spelling of 28185121 in words is "twenty-eight million, one hundred eighty-five thousand, one hundred twenty-one".