28719993 has 4 divisors (see below), whose sum is σ = 38293328. Its totient is φ = 19146660.

The previous prime is 28719989. The next prime is 28720037. The reversal of 28719993 is 39991782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28719993 - 2² = 28719989 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28719973) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4786663 + ... + 4786668.

It is an arithmetic number, because the mean of its divisors is an integer number (9573332).

Almost surely, 2^28719993 is an apocalyptic number.

It is an amenable number.

28719993 is a deficient number, since it is larger than the sum of its proper divisors (9573335).

28719993 is an equidigital number, since it uses as much as digits as its factorization.

28719993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9573334.

The product of its digits is 244944, while the sum is 48.

The square root of 28719993 is about 5359.1037496955. The cubic root of 28719993 is about 306.2396665679.

The spelling of 28719993 in words is "twenty-eight million, seven hundred nineteen thousand, nine hundred ninety-three".