3956109065981 has 2 divisors, whose sum is σ = 3956109065982. Its totient is φ = 3956109065980.

The previous prime is 3956109065933. The next prime is 3956109066031. The reversal of 3956109065981 is 1895609016593.

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., 3593807398756 + 362301667225 = 1895734^2 + 601915^2 .

It is an emirp because it is prime and its reverse (1895609016593) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3956109065981 - 2²⁶ = 3956041957117 is a prime.

It is a super-2 number, since 2×3956109065981² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3956109068981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1978054532990 + 1978054532991.

It is an arithmetic number, because the mean of its divisors is an integer number (1978054532991).

Almost surely, 2^{3956109065981} is an apocalyptic number.

It is an amenable number.

3956109065981 is a deficient number, since it is larger than the sum of its proper divisors (1).

3956109065981 is an equidigital number, since it uses as much as digits as its factorization.

3956109065981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15746400, while the sum is 62.

The spelling of 3956109065981 in words is "three trillion, nine hundred fifty-six billion, one hundred nine million, sixty-five thousand, nine hundred eighty-one".