28921187 has 2 divisors, whose sum is σ = 28921188. Its totient is φ = 28921186.

The previous prime is 28921183. The next prime is 28921201. The reversal of 28921187 is 78112982.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28921187 - 2² = 28921183 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28921187.

It is not a weakly prime, because it can be changed into another prime (28921183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14460593 + 14460594.

It is an arithmetic number, because the mean of its divisors is an integer number (14460594).

Almost surely, 2^28921187 is an apocalyptic number.

28921187 is a deficient number, since it is larger than the sum of its proper divisors (1).

28921187 is an equidigital number, since it uses as much as digits as its factorization.

28921187 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 38.

The square root of 28921187 is about 5377.8422252796. The cubic root of 28921187 is about 306.9531099362.

The spelling of 28921187 in words is "twenty-eight million, nine hundred twenty-one thousand, one hundred eighty-seven".