1211978477569 has 2 divisors, whose sum is σ = 1211978477570. Its totient is φ = 1211978477568.

The previous prime is 1211978477519. The next prime is 1211978477573. The reversal of 1211978477569 is 9657748791121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1078689960000 + 133288517569 = 1038600^2 + 365087^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211978477569 - 2⁹ = 1211978477057 is a prime.

It is a super-2 number, since 2×1211978477569² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1211978477519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605989238784 + 605989238785.

It is an arithmetic number, because the mean of its divisors is an integer number (605989238785).

Almost surely, 2^{1211978477569} is an apocalyptic number.

It is an amenable number.

1211978477569 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211978477569 is an equidigital number, since it uses as much as digits as its factorization.

1211978477569 is an evil number, because the sum of its binary digits is even.

The product of its digits is 53343360, while the sum is 67.

The spelling of 1211978477569 in words is "one trillion, two hundred eleven billion, nine hundred seventy-eight million, four hundred seventy-seven thousand, five hundred sixty-nine".