28720344749 has 8 divisors (see below), whose sum is σ = 29035623960. Its totient is φ = 28405672000.

The previous prime is 28720344739. The next prime is 28720344781. The reversal of 28720344749 is 94744302782.

It can be written as a sum of positive squares in 4 ways, for example, as 8714222500 + 20006122249 = 93350^2 + 141443^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28720344749 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28720344697 and 28720344706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28720344739) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56054 + ... + 246135.

It is an arithmetic number, because the mean of its divisors is an integer number (3629452995).

Almost surely, 2^28720344749 is an apocalyptic number.

It is an amenable number.

28720344749 is a deficient number, since it is larger than the sum of its proper divisors (315279211).

28720344749 is a wasteful number, since it uses less digits than its factorization.

28720344749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303231.

The product of its (nonzero) digits is 2709504, while the sum is 50.

The spelling of 28720344749 in words is "twenty-eight billion, seven hundred twenty million, three hundred forty-four thousand, seven hundred forty-nine".