1205655779 has 2 divisors, whose sum is σ = 1205655780. Its totient is φ = 1205655778.

The previous prime is 1205655769. The next prime is 1205655851. The reversal of 1205655779 is 9775565021.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1205655779 - 2⁸ = 1205655523 is a prime.

It is not a weakly prime, because it can be changed into another prime (1205655709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 602827889 + 602827890.

It is an arithmetic number, because the mean of its divisors is an integer number (602827890).

Almost surely, 2^1205655779 is an apocalyptic number.

1205655779 is a deficient number, since it is larger than the sum of its proper divisors (1).

1205655779 is an equidigital number, since it uses as much as digits as its factorization.

1205655779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 661500, while the sum is 47.

The square root of 1205655779 is about 34722.5543271229. The cubic root of 1205655779 is about 1064.3254426278.

The spelling of 1205655779 in words is "one billion, two hundred five million, six hundred fifty-five thousand, seven hundred seventy-nine".