8131771321 has 2 divisors, whose sum is σ = 8131771322. Its totient is φ = 8131771320.

The previous prime is 8131771309. The next prime is 8131771327. The reversal of 8131771321 is 1231771318.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4561111296 + 3570660025 = 67536^2 + 59755^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8131771321 is a prime.

It is a super-2 number, since 2×8131771321² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (8131771327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4065885660 + 4065885661.

It is an arithmetic number, because the mean of its divisors is an integer number (4065885661).

Almost surely, 2^8131771321 is an apocalyptic number.

It is an amenable number.

8131771321 is a deficient number, since it is larger than the sum of its proper divisors (1).

8131771321 is an equidigital number, since it uses as much as digits as its factorization.

8131771321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 34.

The square root of 8131771321 is about 90176.3345950588. The cubic root of 8131771321 is about 2010.9211985775.

The spelling of 8131771321 in words is "eight billion, one hundred thirty-one million, seven hundred seventy-one thousand, three hundred twenty-one".