28128511731 has 8 divisors (see below), whose sum is σ = 38302654464. Its totient is φ = 18353355080.

The previous prime is 28128511693. The next prime is 28128511759. The reversal of 28128511731 is 13711582182.

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

It is a cyclic number.

It is not a de Polignac number, because 28128511731 - 2¹⁴ = 28128495347 is a prime.

It is a super-2 number, since 2×28128511731² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28128511731.

It is not an unprimeable number, because it can be changed into a prime (28128511781) 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, 99746355 + ... + 99746636.

It is an arithmetic number, because the mean of its divisors is an integer number (4787831808).

Almost surely, 2^28128511731 is an apocalyptic number.

28128511731 is a deficient number, since it is larger than the sum of its proper divisors (10174142733).

28128511731 is a wasteful number, since it uses less digits than its factorization.

28128511731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199493041.

The product of its digits is 26880, while the sum is 39.

The spelling of 28128511731 in words is "twenty-eight billion, one hundred twenty-eight million, five hundred eleven thousand, seven hundred thirty-one".