3951128791321 has 2 divisors, whose sum is σ = 3951128791322. Its totient is φ = 3951128791320.

The previous prime is 3951128791301. The next prime is 3951128791327. The reversal of 3951128791321 is 1231978211593.

3951128791321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2920424655625 + 1030704135696 = 1708925^2 + 1015236^2 .

It is an emirp because it is prime and its reverse (1231978211593) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3951128791321 - 2³¹ = 3948981307673 is a prime.

It is a super-2 number, since 2×3951128791321² (a number of 26 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3951128791327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1975564395660 + 1975564395661.

It is an arithmetic number, because the mean of its divisors is an integer number (1975564395661).

Almost surely, 2^{3951128791321} is an apocalyptic number.

It is an amenable number.

3951128791321 is a deficient number, since it is larger than the sum of its proper divisors (1).

3951128791321 is an equidigital number, since it uses as much as digits as its factorization.

3951128791321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 816480, while the sum is 52.

The spelling of 3951128791321 in words is "three trillion, nine hundred fifty-one billion, one hundred twenty-eight million, seven hundred ninety-one thousand, three hundred twenty-one".