1916809791121 has 9 divisors (see below), whose sum is σ = 1985227466833. Its totient is φ = 1850674136080.

The previous prime is 1916809791109. The next prime is 1916809791163. The reversal of 1916809791121 is 1211979086191.

The square root of 1916809791121 is 1384489.

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

It can be written as a sum of positive squares in 4 ways, for example, as 899293752721 + 1017516038400 = 948311^2 + 1008720^2 .

It is not a de Polignac number, because 1916809791121 - 2²³ = 1916801402513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1916809791101) 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 8 ways as a sum of consecutive naturals, for example, 40126311 + ... + 40174051.

Almost surely, 2^{1916809791121} is an apocalyptic number.

1916809791121 is the 1384489-th square number.

1916809791121 is the 692245-th centered octagonal number.

It is an amenable number.

1916809791121 is a deficient number, since it is larger than the sum of its proper divisors (68417675712).

1916809791121 is an frugal number, since it uses more digits than its factorization.

1916809791121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95540 (or 47770 counting only the distinct ones).

The product of its (nonzero) digits is 489888, while the sum is 55.

The spelling of 1916809791121 in words is "one trillion, nine hundred sixteen billion, eight hundred nine million, seven hundred ninety-one thousand, one hundred twenty-one".