1261335443664 has 40 divisors (see below), whose sum is σ = 3311867115232. Its totient is φ = 413552603520.

The previous prime is 1261335443659. The next prime is 1261335443713. The reversal of 1261335443664 is 4663445331621.

It is a Harshad number since it is a multiple of its sum of digits (48).

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, 215389054 + ... + 215394909.

Almost surely, 2^{1261335443664} is an apocalyptic number.

It is an amenable number.

1261335443664 is an abundant number, since it is smaller than the sum of its proper divisors (2050531671568).

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

1261335443664 is a wasteful number, since it uses less digits than its factorization.

1261335443664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430784035 (or 430784029 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 48.

The spelling of 1261335443664 in words is "one trillion, two hundred sixty-one billion, three hundred thirty-five million, four hundred forty-three thousand, six hundred sixty-four".