1918997907841 has 45 divisors (see below), whose sum is σ = 2379563027331. Its totient is φ = 1547168245056.

The previous prime is 1918997907839. The next prime is 1918997907949. The reversal of 1918997907841 is 1487097998191.

The square root of 1918997907841 is 1385279.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1494029513025 + 424968394816 = 1222305^2 + 651896^2 .

It is not a de Polignac number, because 1918997907841 - 2¹ = 1918997907839 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1918997901841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1153936576 + ... + 1153938238.

Almost surely, 2^{1918997907841} is an apocalyptic number.

1918997907841 is the 1385279-th square number.

1918997907841 is the 692640-th centered octagonal number.

It is an amenable number.

1918997907841 is a deficient number, since it is larger than the sum of its proper divisors (460565119490).

1918997907841 is an frugal number, since it uses more digits than its factorization.

1918997907841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3388 (or 1687 counting only the distinct ones).

The product of its (nonzero) digits is 82301184, while the sum is 73.

The spelling of 1918997907841 in words is "one trillion, nine hundred eighteen billion, nine hundred ninety-seven million, nine hundred seven thousand, eight hundred forty-one".