28158443721 has 8 divisors (see below), whose sum is σ = 41716212960. Its totient is φ = 18772295796.

The previous prime is 28158443717. The next prime is 28158443759. The reversal of 28158443721 is 12734485182.

28158443721 is a `hidden beast` number, since 2 + 8 + 1 + 584 + 43 + 7 + 21 = 666.

It is not a de Polignac number, because 28158443721 - 2² = 28158443717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28158443701) 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, 521452635 + ... + 521452688.

It is an arithmetic number, because the mean of its divisors is an integer number (5214526620).

Almost surely, 2^28158443721 is an apocalyptic number.

It is an amenable number.

28158443721 is a deficient number, since it is larger than the sum of its proper divisors (13557769239).

28158443721 is a wasteful number, since it uses less digits than its factorization.

28158443721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1042905332 (or 1042905326 counting only the distinct ones).

The product of its digits is 430080, while the sum is 45.

The spelling of 28158443721 in words is "twenty-eight billion, one hundred fifty-eight million, four hundred forty-three thousand, seven hundred twenty-one".