28215891840 has 128 divisors (see below), whose sum is σ = 90113328000. Its totient is φ = 7509583872.

The previous prime is 28215891811. The next prime is 28215891857. The reversal of 28215891840 is 4819851282.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×28215891840² (a number of 22 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 28215891840.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 990111 + ... + 1018209.

It is an arithmetic number, because the mean of its divisors is an integer number (704010375).

Almost surely, 2^28215891840 is an apocalyptic number.

28215891840 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 28215891840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45056664000).

28215891840 is an abundant number, since it is smaller than the sum of its proper divisors (61897436160).

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

28215891840 is a wasteful number, since it uses less digits than its factorization.

28215891840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28644 (or 28632 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 48.

The spelling of 28215891840 in words is "twenty-eight billion, two hundred fifteen million, eight hundred ninety-one thousand, eight hundred forty".