781161 has 4 divisors (see below), whose sum is σ = 1041552. Its totient is φ = 520772.

The previous prime is 781139. The next prime is 781163. The reversal of 781161 is 161187.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 781161 - 2⁵ = 781129 is a prime.

It is a super-2 number, since 2×781161² = 1220425015842, which contains 22 as substring.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (781163) 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, 130191 + ... + 130196.

It is an arithmetic number, because the mean of its divisors is an integer number (260388).

2⁷⁸¹¹⁶¹ is an apocalyptic number.

It is an amenable number.

781161 is a deficient number, since it is larger than the sum of its proper divisors (260391).

781161 is a wasteful number, since it uses less digits than its factorization.

781161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260390.

The product of its digits is 336, while the sum is 24.

The square root of 781161 is about 883.8331290464. The cubic root of 781161 is about 92.0972899593.

The spelling of 781161 in words is "seven hundred eighty-one thousand, one hundred sixty-one".