1261263353556 has 24 divisors (see below), whose sum is σ = 2954398991040. Its totient is φ = 418785236992.

The previous prime is 1261263353549. The next prime is 1261263353569. The reversal of 1261263353556 is 6553533621621.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 204481896 + ... + 204488063.

It is an arithmetic number, because the mean of its divisors is an integer number (123099957960).

Almost surely, 2^{1261263353556} is an apocalyptic number.

It is an amenable number.

1261263353556 is an abundant number, since it is smaller than the sum of its proper divisors (1693135637484).

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

1261263353556 is a wasteful number, since it uses less digits than its factorization.

1261263353556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408970223 (or 408970221 counting only the distinct ones).

The product of its digits is 2916000, while the sum is 48.

The spelling of 1261263353556 in words is "one trillion, two hundred sixty-one billion, two hundred sixty-three million, three hundred fifty-three thousand, five hundred fifty-six".