1291215595761 has 168 divisors, whose sum is σ = 2439739556520. Its totient is φ = 681039358272.

The previous prime is 1291215595759. The next prime is 1291215595771. The reversal of 1291215595761 is 1675955121921.

1291215595761 is a `hidden beast` number, since 1 + 2 + 9 + 1 + 2 + 15 + 59 + 576 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 138770405361 + 1152445190400 = 372519^2 + 1073520^2 .

It is not a de Polignac number, because 1291215595761 - 2¹ = 1291215595759 is a prime.

It is a super-2 number, since 2×1291215595761² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1291215595698 and 1291215595707.

It is not an unprimeable number, because it can be changed into a prime (1291215595771) 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 in 167 ways as a sum of consecutive naturals, for example, 78470811 + ... + 78487263.

It is an arithmetic number, because the mean of its divisors is an integer number (14522259265).

Almost surely, 2^{1291215595761} is an apocalyptic number.

It is an amenable number.

1291215595761 is a deficient number, since it is larger than the sum of its proper divisors (1148523960759).

1291215595761 is an frugal number, since it uses more digits than its factorization.

1291215595761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16524 (or 16476 counting only the distinct ones).

The product of its digits is 1701000, while the sum is 54.

The spelling of 1291215595761 in words is "one trillion, two hundred ninety-one billion, two hundred fifteen million, five hundred ninety-five thousand, seven hundred sixty-one".