28312121280 has 112 divisors (see below), whose sum is σ = 90211741344. Its totient is φ = 7522959360.

The previous prime is 28312121219. The next prime is 28312121287. The reversal of 28312121280 is 8212121382.

It is a super-2 number, since 2×28312121280² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28312121287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 217284 + ... + 322236.

Almost surely, 2^28312121280 is an apocalyptic number.

28312121280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28312121280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45105870672).

28312121280 is an abundant number, since it is smaller than the sum of its proper divisors (61899620064).

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

28312121280 is a wasteful number, since it uses less digits than its factorization.

28312121280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105254 (or 105244 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 30.

The spelling of 28312121280 in words is "twenty-eight billion, three hundred twelve million, one hundred twenty-one thousand, two hundred eighty".