8121647771 has 2 divisors, whose sum is σ = 8121647772. Its totient is φ = 8121647770.

The previous prime is 8121647767. The next prime is 8121647801. The reversal of 8121647771 is 1777461218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8121647771 - 2² = 8121647767 is a prime.

It is a super-2 number, since 2×8121647771² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (8121647671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4060823885 + 4060823886.

It is an arithmetic number, because the mean of its divisors is an integer number (4060823886).

Almost surely, 2^8121647771 is an apocalyptic number.

8121647771 is a deficient number, since it is larger than the sum of its proper divisors (1).

8121647771 is an equidigital number, since it uses as much as digits as its factorization.

8121647771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 131712, while the sum is 44.

The square root of 8121647771 is about 90120.1851473908. The cubic root of 8121647771 is about 2010.0863613958.

The spelling of 8121647771 in words is "eight billion, one hundred twenty-one million, six hundred forty-seven thousand, seven hundred seventy-one".