28157820420 has 96 divisors (see below), whose sum is σ = 80017701120. Its totient is φ = 7396945920.

The previous prime is 28157820413. The next prime is 28157820421. The reversal of 28157820420 is 2402875182.

It is not an unprimeable number, because it can be changed into a prime (28157820421) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7977216 + ... + 7980744.

It is an arithmetic number, because the mean of its divisors is an integer number (833517720).

Almost surely, 2^28157820420 is an apocalyptic number.

28157820420 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 28157820420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40008850560).

28157820420 is an abundant number, since it is smaller than the sum of its proper divisors (51859880700).

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

28157820420 is a wasteful number, since it uses less digits than its factorization.

28157820420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5485 (or 5483 counting only the distinct ones).

The product of its (nonzero) digits is 71680, while the sum is 39.

The spelling of 28157820420 in words is "twenty-eight billion, one hundred fifty-seven million, eight hundred twenty thousand, four hundred twenty".