28691935138 has 4 divisors (see below), whose sum is σ = 43037902710. Its totient is φ = 14345967568.

The previous prime is 28691935133. The next prime is 28691935163. The reversal of 28691935138 is 83153919682.

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., 27626761369 + 1065173769 = 166213^2 + 32637^2 .

It is not an unprimeable number, because it can be changed into a prime (28691935133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7172983783 + ... + 7172983786.

Almost surely, 2^28691935138 is an apocalyptic number.

28691935138 is a deficient number, since it is larger than the sum of its proper divisors (14345967572).

28691935138 is a wasteful number, since it uses less digits than its factorization.

28691935138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14345967571.

The product of its digits is 2799360, while the sum is 55.

The spelling of 28691935138 in words is "twenty-eight billion, six hundred ninety-one million, nine hundred thirty-five thousand, one hundred thirty-eight".