28355560121 has 4 divisors (see below), whose sum is σ = 32406354432. Its totient is φ = 24304765812.

The previous prime is 28355560087. The next prime is 28355560141. The reversal of 28355560121 is 12106555382.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28355560121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28355560141) 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, 2025397145 + ... + 2025397158.

It is an arithmetic number, because the mean of its divisors is an integer number (8101588608).

Almost surely, 2^28355560121 is an apocalyptic number.

It is an amenable number.

28355560121 is a deficient number, since it is larger than the sum of its proper divisors (4050794311).

28355560121 is an equidigital number, since it uses as much as digits as its factorization.

28355560121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4050794310.

The product of its (nonzero) digits is 72000, while the sum is 38.

The spelling of 28355560121 in words is "twenty-eight billion, three hundred fifty-five million, five hundred sixty thousand, one hundred twenty-one".