28321216881 has 4 divisors (see below), whose sum is σ = 37761622512. Its totient is φ = 18880811252.

The previous prime is 28321216877. The next prime is 28321216883. The reversal of 28321216881 is 18861212382.

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 not a de Polignac number, because 28321216881 - 2² = 28321216877 is a prime.

It is a super-2 number, since 2×28321216881² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28321216883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4720202811 + ... + 4720202816.

It is an arithmetic number, because the mean of its divisors is an integer number (9440405628).

Almost surely, 2^28321216881 is an apocalyptic number.

It is an amenable number.

28321216881 is a deficient number, since it is larger than the sum of its proper divisors (9440405631).

28321216881 is an equidigital number, since it uses as much as digits as its factorization.

28321216881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9440405630.

The product of its digits is 73728, while the sum is 42.

The spelling of 28321216881 in words is "twenty-eight billion, three hundred twenty-one million, two hundred sixteen thousand, eight hundred eighty-one".