28056111721 has 24 divisors (see below), whose sum is σ = 34202546784. Its totient is φ = 22741741440.

The previous prime is 28056111719. The next prime is 28056111737. The reversal of 28056111721 is 12711165082.

It is not a de Polignac number, because 28056111721 - 2¹ = 28056111719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28056111751) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 140295 + ... + 275308.

It is an arithmetic number, because the mean of its divisors is an integer number (1425106116).

Almost surely, 2^28056111721 is an apocalyptic number.

It is an amenable number.

28056111721 is a deficient number, since it is larger than the sum of its proper divisors (6146435063).

28056111721 is a wasteful number, since it uses less digits than its factorization.

28056111721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415669 (or 415650 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 34.

The spelling of 28056111721 in words is "twenty-eight billion, fifty-six million, one hundred eleven thousand, seven hundred twenty-one".