1261555543604 has 12 divisors (see below), whose sum is σ = 2220942095904. Its totient is φ = 627000659064.

The previous prime is 1261555543603. The next prime is 1261555543631. The reversal of 1261555543604 is 4063455551621.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261555543603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 944277434 + ... + 944278769.

It is an arithmetic number, because the mean of its divisors is an integer number (185078507992).

Almost surely, 2^{1261555543604} is an apocalyptic number.

It is an amenable number.

1261555543604 is a deficient number, since it is larger than the sum of its proper divisors (959386552300).

1261555543604 is a wasteful number, since it uses less digits than its factorization.

1261555543604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1888556374 (or 1888556372 counting only the distinct ones).

The product of its (nonzero) digits is 2160000, while the sum is 47.

The spelling of 1261555543604 in words is "one trillion, two hundred sixty-one billion, five hundred fifty-five million, five hundred forty-three thousand, six hundred four".