28161411821 has 2 divisors, whose sum is σ = 28161411822. Its totient is φ = 28161411820.

The previous prime is 28161411799. The next prime is 28161411851. The reversal of 28161411821 is 12811416182.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27576255721 + 585156100 = 166061^2 + 24190^2 .

It is a cyclic number.

It is not a de Polignac number, because 28161411821 - 2¹⁸ = 28161149677 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28161411851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14080705910 + 14080705911.

It is an arithmetic number, because the mean of its divisors is an integer number (14080705911).

Almost surely, 2^28161411821 is an apocalyptic number.

It is an amenable number.

28161411821 is a deficient number, since it is larger than the sum of its proper divisors (1).

28161411821 is an equidigital number, since it uses as much as digits as its factorization.

28161411821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6144, while the sum is 35.

The spelling of 28161411821 in words is "twenty-eight billion, one hundred sixty-one million, four hundred eleven thousand, eight hundred twenty-one".