1781081131 has 4 divisors (see below), whose sum is σ = 1782157672. Its totient is φ = 1780004592.

The previous prime is 1781081129. The next prime is 1781081171. The reversal of 1781081131 is 1311801871.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1311801871 = 773 ⋅1697027.

It is a cyclic number.

It is not a de Polignac number, because 1781081131 - 2¹ = 1781081129 is a prime.

It is a super-2 number, since 2×1781081131² = 6344499990408478322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1781081093 and 1781081102.

It is not an unprimeable number, because it can be changed into a prime (1781081101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 535785 + ... + 539098.

It is an arithmetic number, because the mean of its divisors is an integer number (445539418).

Almost surely, 2^1781081131 is an apocalyptic number.

1781081131 is a deficient number, since it is larger than the sum of its proper divisors (1076541).

1781081131 is a wasteful number, since it uses less digits than its factorization.

1781081131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1076540.

The product of its (nonzero) digits is 1344, while the sum is 31.

The square root of 1781081131 is about 42202.8569056646. The cubic root of 1781081131 is about 1212.1635881949.

The spelling of 1781081131 in words is "one billion, seven hundred eighty-one million, eighty-one thousand, one hundred thirty-one".