28043993 has 2 divisors, whose sum is σ = 28043994. Its totient is φ = 28043992.

The previous prime is 28043947. The next prime is 28044011. The reversal of 28043993 is 39934082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27175369 + 868624 = 5213^2 + 932^2 .

It is a cyclic number.

It is not a de Polignac number, because 28043993 - 2⁶ = 28043929 is a prime.

It is not a weakly prime, because it can be changed into another prime (28040993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14021996 + 14021997.

It is an arithmetic number, because the mean of its divisors is an integer number (14021997).

Almost surely, 2^28043993 is an apocalyptic number.

It is an amenable number.

28043993 is a deficient number, since it is larger than the sum of its proper divisors (1).

28043993 is an equidigital number, since it uses as much as digits as its factorization.

28043993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 38.

The square root of 28043993 is about 5295.6579383491. The cubic root of 28043993 is about 303.8178480873.

The spelling of 28043993 in words is "twenty-eight million, forty-three thousand, nine hundred ninety-three".