1269957777661 has 2 divisors, whose sum is σ = 1269957777662. Its totient is φ = 1269957777660.

The previous prime is 1269957777637. The next prime is 1269957777667. The reversal of 1269957777661 is 1667777599621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 691284159225 + 578673618436 = 831435^2 + 760706^2 .

It is a cyclic number.

It is not a de Polignac number, because 1269957777661 - 2⁵ = 1269957777629 is a prime.

It is a super-2 number, since 2×1269957777661² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1269957777667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 634978888830 + 634978888831.

It is an arithmetic number, because the mean of its divisors is an integer number (634978888831).

Almost surely, 2^{1269957777661} is an apocalyptic number.

It is an amenable number.

1269957777661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1269957777661 is an equidigital number, since it uses as much as digits as its factorization.

1269957777661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 420078960, while the sum is 73.

The spelling of 1269957777661 in words is "one trillion, two hundred sixty-nine billion, nine hundred fifty-seven million, seven hundred seventy-seven thousand, six hundred sixty-one".