1278932216761 has 2 divisors, whose sum is σ = 1278932216762. Its totient is φ = 1278932216760.

The previous prime is 1278932216717. The next prime is 1278932216777. The reversal of 1278932216761 is 1676122398721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1278835292736 + 96924025 = 1130856^2 + 9845^2 .

It is an emirp because it is prime and its reverse (1676122398721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1278932216761 - 2¹³ = 1278932208569 is a prime.

It is a super-2 number, since 2×1278932216761² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1278932214761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639466108380 + 639466108381.

It is an arithmetic number, because the mean of its divisors is an integer number (639466108381).

Almost surely, 2^{1278932216761} is an apocalyptic number.

It is an amenable number.

1278932216761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278932216761 is an equidigital number, since it uses as much as digits as its factorization.

1278932216761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3048192, while the sum is 55.

The spelling of 1278932216761 in words is "one trillion, two hundred seventy-eight billion, nine hundred thirty-two million, two hundred sixteen thousand, seven hundred sixty-one".