1217220638779 has 2 divisors, whose sum is σ = 1217220638780. Its totient is φ = 1217220638778.

The previous prime is 1217220638687. The next prime is 1217220638813. The reversal of 1217220638779 is 9778360227121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1217220638779 - 2³³ = 1208630704187 is a prime.

It is a super-2 number, since 2×1217220638779² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1217220635779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608610319389 + 608610319390.

It is an arithmetic number, because the mean of its divisors is an integer number (608610319390).

Almost surely, 2^{1217220638779} is an apocalyptic number.

1217220638779 is a deficient number, since it is larger than the sum of its proper divisors (1).

1217220638779 is an equidigital number, since it uses as much as digits as its factorization.

1217220638779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3556224, while the sum is 55.

The spelling of 1217220638779 in words is "one trillion, two hundred seventeen billion, two hundred twenty million, six hundred thirty-eight thousand, seven hundred seventy-nine".