121631265781 has 2 divisors, whose sum is σ = 121631265782. Its totient is φ = 121631265780.

The previous prime is 121631265731. The next prime is 121631265787. The reversal of 121631265781 is 187562136121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 117231596881 + 4399668900 = 342391^2 + 66330^2 .

It is a cyclic number.

It is not a de Polignac number, because 121631265781 - 2¹³ = 121631257589 is a prime.

It is a super-2 number, since 2×121631265781² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121631265787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60815632890 + 60815632891.

It is an arithmetic number, because the mean of its divisors is an integer number (60815632891).

Almost surely, 2^121631265781 is an apocalyptic number.

It is an amenable number.

121631265781 is a deficient number, since it is larger than the sum of its proper divisors (1).

121631265781 is an equidigital number, since it uses as much as digits as its factorization.

121631265781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 43.

The spelling of 121631265781 in words is "one hundred twenty-one billion, six hundred thirty-one million, two hundred sixty-five thousand, seven hundred eighty-one".