28721497288 has 128 divisors (see below), whose sum is σ = 63540288000. Its totient is φ = 12032824320.

The previous prime is 28721497283. The next prime is 28721497309. The reversal of 28721497288 is 88279412782.

It is a super-3 number, since 3×28721497288³ (a number of 32 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (58) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (28721497283) 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, 9296448 + ... + 9299536.

It is an arithmetic number, because the mean of its divisors is an integer number (496408500).

Almost surely, 2^28721497288 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28721497288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31770144000).

28721497288 is an abundant number, since it is smaller than the sum of its proper divisors (34818790712).

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

28721497288 is a wasteful number, since it uses less digits than its factorization.

28721497288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3275 (or 3271 counting only the distinct ones).

The product of its digits is 7225344, while the sum is 58.

The spelling of 28721497288 in words is "twenty-eight billion, seven hundred twenty-one million, four hundred ninety-seven thousand, two hundred eighty-eight".