28781299993 has 4 divisors (see below), whose sum is σ = 28849664548. Its totient is φ = 28712935440.

The previous prime is 28781299979. The next prime is 28781300017. The reversal of 28781299993 is 39999218782.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3100596489 + 25680703504 = 55683^2 + 160252^2 .

It is a cyclic number.

It is not a de Polignac number, because 28781299993 - 2¹³ = 28781291801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28781299913) 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, 34181646 + ... + 34182487.

It is an arithmetic number, because the mean of its divisors is an integer number (7212416137).

Almost surely, 2^28781299993 is an apocalyptic number.

It is an amenable number.

28781299993 is a deficient number, since it is larger than the sum of its proper divisors (68364555).

28781299993 is an equidigital number, since it uses as much as digits as its factorization.

28781299993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68364554.

The product of its digits is 35271936, while the sum is 67.

The spelling of 28781299993 in words is "twenty-eight billion, seven hundred eighty-one million, two hundred ninety-nine thousand, nine hundred ninety-three".