28138743731 has 4 divisors (see below), whose sum is σ = 32158564272. Its totient is φ = 24118923192.

The previous prime is 28138743667. The next prime is 28138743749. The reversal of 28138743731 is 13734783182.

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

It is not a de Polignac number, because 28138743731 - 2⁶ = 28138743667 is a prime.

It is a super-2 number, since 2×28138743731² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28138743751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2009910260 + ... + 2009910273.

It is an arithmetic number, because the mean of its divisors is an integer number (8039641068).

Almost surely, 2^28138743731 is an apocalyptic number.

28138743731 is a deficient number, since it is larger than the sum of its proper divisors (4019820541).

28138743731 is an equidigital number, since it uses as much as digits as its factorization.

28138743731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4019820540.

The product of its digits is 677376, while the sum is 47.

The spelling of 28138743731 in words is "twenty-eight billion, one hundred thirty-eight million, seven hundred forty-three thousand, seven hundred thirty-one".