28320642473 has 4 divisors (see below), whose sum is σ = 28321474260. Its totient is φ = 28319810688.

The previous prime is 28320642461. The next prime is 28320642487. The reversal of 28320642473 is 37424602382.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18691538089 + 9629104384 = 136717^2 + 98128^2 .

It is a cyclic number.

It is not a de Polignac number, because 28320642473 - 2⁶ = 28320642409 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28320642473.

It is not an unprimeable number, because it can be changed into a prime (28320642673) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 362540 + ... + 433677.

It is an arithmetic number, because the mean of its divisors is an integer number (7080368565).

Almost surely, 2^28320642473 is an apocalyptic number.

It is an amenable number.

28320642473 is a deficient number, since it is larger than the sum of its proper divisors (831787).

28320642473 is an equidigital number, since it uses as much as digits as its factorization.

28320642473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831786.

The product of its (nonzero) digits is 387072, while the sum is 41.

The spelling of 28320642473 in words is "twenty-eight billion, three hundred twenty million, six hundred forty-two thousand, four hundred seventy-three".