27020721817 has 2 divisors, whose sum is σ = 27020721818. Its totient is φ = 27020721816.

The previous prime is 27020721719. The next prime is 27020721821. The reversal of 27020721817 is 71812702072.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25007943321 + 2012778496 = 158139^2 + 44864^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27020721817 is a prime.

It is not a weakly prime, because it can be changed into another prime (27020721857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13510360908 + 13510360909.

It is an arithmetic number, because the mean of its divisors is an integer number (13510360909).

Almost surely, 2^27020721817 is an apocalyptic number.

It is an amenable number.

27020721817 is a deficient number, since it is larger than the sum of its proper divisors (1).

27020721817 is an equidigital number, since it uses as much as digits as its factorization.

27020721817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21952, while the sum is 37.

The spelling of 27020721817 in words is "twenty-seven billion, twenty million, seven hundred twenty-one thousand, eight hundred seventeen".