28539231021 has 96 divisors (see below), whose sum is σ = 49415857920. Its totient is φ = 15533586432.

The previous prime is 28539231001. The next prime is 28539231023. The reversal of 28539231021 is 12013293582.

It is not a de Polignac number, because 28539231021 - 2⁵ = 28539230989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28539231023) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 28284165 + ... + 28285173.

It is an arithmetic number, because the mean of its divisors is an integer number (514748520).

Almost surely, 2^28539231021 is an apocalyptic number.

28539231021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28539231021 is a deficient number, since it is larger than the sum of its proper divisors (20876626899).

28539231021 is a wasteful number, since it uses less digits than its factorization.

28539231021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1315 (or 1312 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

It can be divided in two parts, 28539 and 231021, that added together give a triangular number (259560 = T₇₂₀).

The spelling of 28539231021 in words is "twenty-eight billion, five hundred thirty-nine million, two hundred thirty-one thousand, twenty-one".