1691378123243 has 16 divisors (see below), whose sum is σ = 1803937443840. Its totient is φ = 1580272957056.

The previous prime is 1691378123131. The next prime is 1691378123261. The reversal of 1691378123243 is 3423218731961.

It is not a de Polignac number, because 1691378123243 - 2¹⁰ = 1691378122219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1691378123191 and 1691378123200.

It is not an unprimeable number, because it can be changed into a prime (1691378123543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27869630 + ... + 27930252.

It is an arithmetic number, because the mean of its divisors is an integer number (112746090240).

Almost surely, 2^{1691378123243} is an apocalyptic number.

1691378123243 is a deficient number, since it is larger than the sum of its proper divisors (112559320597).

1691378123243 is a wasteful number, since it uses less digits than its factorization.

1691378123243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72586.

The product of its digits is 1306368, while the sum is 50.

The spelling of 1691378123243 in words is "one trillion, six hundred ninety-one billion, three hundred seventy-eight million, one hundred twenty-three thousand, two hundred forty-three".