28720797439 has 4 divisors (see below), whose sum is σ = 28830002256. Its totient is φ = 28611592624.

The previous prime is 28720797433. The next prime is 28720797463. The reversal of 28720797439 is 93479702782.

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

It is a cyclic number.

It is not a de Polignac number, because 28720797439 - 2⁹ = 28720796927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28720797433) 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, 54602014 + ... + 54602539.

It is an arithmetic number, because the mean of its divisors is an integer number (7207500564).

Almost surely, 2^28720797439 is an apocalyptic number.

28720797439 is a deficient number, since it is larger than the sum of its proper divisors (109204817).

28720797439 is a wasteful number, since it uses less digits than its factorization.

28720797439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109204816.

The product of its (nonzero) digits is 10668672, while the sum is 58.

The spelling of 28720797439 in words is "twenty-eight billion, seven hundred twenty million, seven hundred ninety-seven thousand, four hundred thirty-nine".