27721852861 has 2 divisors, whose sum is σ = 27721852862. Its totient is φ = 27721852860.

The previous prime is 27721852849. The next prime is 27721852897. The reversal of 27721852861 is 16825812772.

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., 20049144025 + 7672708836 = 141595^2 + 87594^2 .

It is a cyclic number.

It is not a de Polignac number, because 27721852861 - 2³¹ = 25574369213 is a prime.

It is a super-2 number, since 2×27721852861² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27721802861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13860926430 + 13860926431.

It is an arithmetic number, because the mean of its divisors is an integer number (13860926431).

Almost surely, 2^27721852861 is an apocalyptic number.

It is an amenable number.

27721852861 is a deficient number, since it is larger than the sum of its proper divisors (1).

27721852861 is an equidigital number, since it uses as much as digits as its factorization.

27721852861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 752640, while the sum is 49.

The spelling of 27721852861 in words is "twenty-seven billion, seven hundred twenty-one million, eight hundred fifty-two thousand, eight hundred sixty-one".