28728887738 has 4 divisors (see below), whose sum is σ = 43093331610. Its totient is φ = 14364443868.

The previous prime is 28728887731. The next prime is 28728887749. The reversal of 28728887738 is 83778882782.

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

It can be written as a sum of positive squares in only one way, i.e., 22639114369 + 6089773369 = 150463^2 + 78037^2 .

It is not an unprimeable number, because it can be changed into a prime (28728887731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7182221933 + ... + 7182221936.

Almost surely, 2^28728887738 is an apocalyptic number.

28728887738 is a deficient number, since it is larger than the sum of its proper divisors (14364443872).

28728887738 is a wasteful number, since it uses less digits than its factorization.

28728887738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14364443871.

The product of its digits is 134873088, while the sum is 68.

The spelling of 28728887738 in words is "twenty-eight billion, seven hundred twenty-eight million, eight hundred eighty-seven thousand, seven hundred thirty-eight".