1223261266556 has 36 divisors (see below), whose sum is σ = 2621274150600. Its totient is φ = 496662467616.

The previous prime is 1223261266517. The next prime is 1223261266639. The reversal of 1223261266556 is 6556621623221.

It is a super-2 number, since 2×1223261266556² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1223261266556.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 164236511 + ... + 164243958.

It is an arithmetic number, because the mean of its divisors is an integer number (72813170850).

Almost surely, 2^{1223261266556} is an apocalyptic number.

It is an amenable number.

1223261266556 is an abundant number, since it is smaller than the sum of its proper divisors (1398012884044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1223261266556 is a wasteful number, since it uses less digits than its factorization.

1223261266556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328480506 (or 328480497 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 47.

Adding to 1223261266556 its reverse (6556621623221), we get a palindrome (7779882889777).

The spelling of 1223261266556 in words is "one trillion, two hundred twenty-three billion, two hundred sixty-one million, two hundred sixty-six thousand, five hundred fifty-six".