81321015371 has 2 divisors, whose sum is σ = 81321015372. Its totient is φ = 81321015370.

The previous prime is 81321015319. The next prime is 81321015389. The reversal of 81321015371 is 17351012318.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81321015371 is a prime.

It is a super-2 number, since 2×81321015371² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81321011371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40660507685 + 40660507686.

It is an arithmetic number, because the mean of its divisors is an integer number (40660507686).

Almost surely, 2^81321015371 is an apocalyptic number.

81321015371 is a deficient number, since it is larger than the sum of its proper divisors (1).

81321015371 is an equidigital number, since it uses as much as digits as its factorization.

81321015371 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 32.

Adding to 81321015371 its reverse (17351012318), we get a palindrome (98672027689).

The spelling of 81321015371 in words is "eighty-one billion, three hundred twenty-one million, fifteen thousand, three hundred seventy-one".