28445326781 has 2 divisors, whose sum is σ = 28445326782. Its totient is φ = 28445326780.

The previous prime is 28445326729. The next prime is 28445326783. The reversal of 28445326781 is 18762354482.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25547227225 + 2898099556 = 159835^2 + 53834^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28445326781 is a prime.

It is a super-2 number, since 2×28445326781² (a number of 22 digits) contains 22 as substring.

Together with 28445326783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28445326783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14222663390 + 14222663391.

It is an arithmetic number, because the mean of its divisors is an integer number (14222663391).

Almost surely, 2^28445326781 is an apocalyptic number.

It is an amenable number.

28445326781 is a deficient number, since it is larger than the sum of its proper divisors (1).

28445326781 is an equidigital number, since it uses as much as digits as its factorization.

28445326781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2580480, while the sum is 50.

The spelling of 28445326781 in words is "twenty-eight billion, four hundred forty-five million, three hundred twenty-six thousand, seven hundred eighty-one".