28728393816 has 32 divisors (see below), whose sum is σ = 72047568240. Its totient is φ = 9545920128.

The previous prime is 28728393781. The next prime is 28728393817. The reversal of 28728393816 is 61839382782.

It is a super-2 number, since 2×28728393816² (a number of 22 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28728393817) 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, 1880431 + ... + 1895646.

Almost surely, 2^28728393816 is an apocalyptic number.

It is an amenable number.

28728393816 is an abundant number, since it is smaller than the sum of its proper divisors (43319174424).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28728393816 is a wasteful number, since it uses less digits than its factorization.

28728393816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3776403 (or 3776399 counting only the distinct ones).

The product of its digits is 6967296, while the sum is 57.

The spelling of 28728393816 in words is "twenty-eight billion, seven hundred twenty-eight million, three hundred ninety-three thousand, eight hundred sixteen".