28913040509 has 4 divisors (see below), whose sum is σ = 28913696316. Its totient is φ = 28912384704.

The previous prime is 28913040503. The next prime is 28913040511. The reversal of 28913040509 is 90504031982.

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 18606324025 + 10306716484 = 136405^2 + 101522^2 .

It is a cyclic number.

It is not a de Polignac number, because 28913040509 - 2¹² = 28913036413 is a prime.

It is a super-2 number, since 2×28913040509² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28913040503) 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, 256604 + ... + 351669.

It is an arithmetic number, because the mean of its divisors is an integer number (7228424079).

Almost surely, 2^28913040509 is an apocalyptic number.

It is an amenable number.

28913040509 is a deficient number, since it is larger than the sum of its proper divisors (655807).

28913040509 is an equidigital number, since it uses as much as digits as its factorization.

28913040509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 655806.

The product of its (nonzero) digits is 77760, while the sum is 41.

The spelling of 28913040509 in words is "twenty-eight billion, nine hundred thirteen million, forty thousand, five hundred nine".