28713178721 has 8 divisors (see below), whose sum is σ = 30505956264. Its totient is φ = 26931930880.

The previous prime is 28713178699. The next prime is 28713178729. The reversal of 28713178721 is 12787131782.

It can be written as a sum of positive squares in 4 ways, for example, as 23108560225 + 5604618496 = 152015^2 + 74864^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28713178721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28713178729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2877290 + ... + 2887251.

It is an arithmetic number, because the mean of its divisors is an integer number (3813244533).

Almost surely, 2^28713178721 is an apocalyptic number.

It is an amenable number.

28713178721 is a deficient number, since it is larger than the sum of its proper divisors (1792777543).

28713178721 is a wasteful number, since it uses less digits than its factorization.

28713178721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5764851.

The product of its digits is 263424, while the sum is 47.

The spelling of 28713178721 in words is "twenty-eight billion, seven hundred thirteen million, one hundred seventy-eight thousand, seven hundred twenty-one".