28130405665 has 16 divisors (see below), whose sum is σ = 35832236112. Its totient is φ = 21127163904.

The previous prime is 28130405657. The next prime is 28130405689. The reversal of 28130405665 is 56650403182.

It can be written as a sum of positive squares in 8 ways, for example, as 31259281 + 28099146384 = 5591^2 + 167628^2 .

It is a cyclic number.

It is not a de Polignac number, because 28130405665 - 2³ = 28130405657 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 383064 + ... + 450553.

It is an arithmetic number, because the mean of its divisors is an integer number (2239514757).

Almost surely, 2^28130405665 is an apocalyptic number.

It is an amenable number.

28130405665 is a deficient number, since it is larger than the sum of its proper divisors (7701830447).

28130405665 is a wasteful number, since it uses less digits than its factorization.

28130405665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834036.

The product of its (nonzero) digits is 172800, while the sum is 40.

The spelling of 28130405665 in words is "twenty-eight billion, one hundred thirty million, four hundred five thousand, six hundred sixty-five".