28056123811 has 4 divisors (see below), whose sum is σ = 28056574552. Its totient is φ = 28055673072.

The previous prime is 28056123713. The next prime is 28056123827. The reversal of 28056123811 is 11832165082.

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

It is a cyclic number.

It is not a de Polignac number, because 28056123811 - 2¹⁷ = 28055992739 is a prime.

It is a super-2 number, since 2×28056123811² (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 (28056126811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 113490 + ... + 262663.

It is an arithmetic number, because the mean of its divisors is an integer number (7014143638).

Almost surely, 2^28056123811 is an apocalyptic number.

28056123811 is a deficient number, since it is larger than the sum of its proper divisors (450741).

28056123811 is an equidigital number, since it uses as much as digits as its factorization.

28056123811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450740.

The product of its (nonzero) digits is 23040, while the sum is 37.

Adding to 28056123811 its reverse (11832165082), we get a palindrome (39888288893).

The spelling of 28056123811 in words is "twenty-eight billion, fifty-six million, one hundred twenty-three thousand, eight hundred eleven".