1231355105081 has 2 divisors, whose sum is σ = 1231355105082. Its totient is φ = 1231355105080.

The previous prime is 1231355105047. The next prime is 1231355105087. The reversal of 1231355105081 is 1805015531321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1066830765625 + 164524339456 = 1032875^2 + 405616^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231355105081 - 2³⁸ = 956477198137 is a prime.

It is a super-2 number, since 2×1231355105081² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1231355105087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615677552540 + 615677552541.

It is an arithmetic number, because the mean of its divisors is an integer number (615677552541).

Almost surely, 2^{1231355105081} is an apocalyptic number.

It is an amenable number.

1231355105081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231355105081 is an equidigital number, since it uses as much as digits as its factorization.

1231355105081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18000, while the sum is 35.

The spelling of 1231355105081 in words is "one trillion, two hundred thirty-one billion, three hundred fifty-five million, one hundred five thousand, eighty-one".