28011232520 has 48 divisors (see below), whose sum is σ = 66950750340. Its totient is φ = 10545400832.

The previous prime is 28011232517. The next prime is 28011232549. The reversal of 28011232520 is 2523211082.

It can be written as a sum of positive squares in 6 ways, for example, as 26057062084 + 1954170436 = 161422^2 + 44206^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28011232520.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1199999 + ... + 1223118.

Almost surely, 2^28011232520 is an apocalyptic number.

28011232520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28011232520 is an abundant number, since it is smaller than the sum of its proper divisors (38939517820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28011232520 is a wasteful number, since it uses less digits than its factorization.

28011232520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2423162 (or 2423141 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

It can be divided in two parts, 2801 and 1232520, that added together give a palindrome (1235321).

The spelling of 28011232520 in words is "twenty-eight billion, eleven million, two hundred thirty-two thousand, five hundred twenty".