28305143991 has 48 divisors (see below), whose sum is σ = 42604353792. Its totient is φ = 18089049600.

The previous prime is 28305143989. The next prime is 28305144019. The reversal of 28305143991 is 19934150382.

It is a happy number.

28305143991 is a `hidden beast` number, since 2 + 83 + 0 + 51 + 439 + 91 = 666.

It is not a de Polignac number, because 28305143991 - 2¹ = 28305143989 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28305143291) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14795251 + ... + 14797163.

It is an arithmetic number, because the mean of its divisors is an integer number (887590704).

Almost surely, 2^28305143991 is an apocalyptic number.

28305143991 is a deficient number, since it is larger than the sum of its proper divisors (14299209801).

28305143991 is a wasteful number, since it uses less digits than its factorization.

28305143991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2424 (or 2421 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The spelling of 28305143991 in words is "twenty-eight billion, three hundred five million, one hundred forty-three thousand, nine hundred ninety-one".