1223455566789 has 12 divisors (see below), whose sum is σ = 1871167337676. Its totient is φ = 767658394752.

The previous prime is 1223455566787. The next prime is 1223455566793. The reversal of 1223455566789 is 9876655543221.

1223455566789 is a `hidden beast` number, since 1 + 2 + 2 + 3 + 4 + 5 + 556 + 6 + 78 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 478068530625 + 745387036164 = 691425^2 + 863358^2 .

It is not a de Polignac number, because 1223455566789 - 2¹ = 1223455566787 is a prime.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1223455566787) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3998220654 + ... + 3998220959.

It is an arithmetic number, because the mean of its divisors is an integer number (155930611473).

Almost surely, 2^{1223455566789} is an apocalyptic number.

It is an amenable number.

1223455566789 is a deficient number, since it is larger than the sum of its proper divisors (647711770887).

1223455566789 is a wasteful number, since it uses less digits than its factorization.

1223455566789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7996441636 (or 7996441633 counting only the distinct ones).

The product of its digits is 108864000, while the sum is 63.

It can be divided in two parts, 1223455 and 566789, that added together give a square (1790244 = 1338²).

The spelling of 1223455566789 in words is "one trillion, two hundred twenty-three billion, four hundred fifty-five million, five hundred sixty-six thousand, seven hundred eighty-nine".