27728588821 has 2 divisors, whose sum is σ = 27728588822. Its totient is φ = 27728588820.

The previous prime is 27728588801. The next prime is 27728588857. The reversal of 27728588821 is 12888582772.

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., 24721272900 + 3007315921 = 157230^2 + 54839^2 .

It is a cyclic number.

It is not a de Polignac number, because 27728588821 - 2²¹ = 27726491669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27728588801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13864294410 + 13864294411.

It is an arithmetic number, because the mean of its divisors is an integer number (13864294411).

Almost surely, 2^27728588821 is an apocalyptic number.

It is an amenable number.

27728588821 is a deficient number, since it is larger than the sum of its proper divisors (1).

27728588821 is an equidigital number, since it uses as much as digits as its factorization.

27728588821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8028160, while the sum is 58.

The spelling of 27728588821 in words is "twenty-seven billion, seven hundred twenty-eight million, five hundred eighty-eight thousand, eight hundred twenty-one".