8461781 has 4 divisors (see below), whose sum is σ = 8477964. Its totient is φ = 8445600.

The previous prime is 8461777. The next prime is 8461787. The reversal of 8461781 is 1871648.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6682225 + 1779556 = 2585^2 + 1334^2 .

It is a cyclic number.

It is not a de Polignac number, because 8461781 - 2² = 8461777 is a prime.

It is a super-2 number, since 2×8461781² = 143203475383922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8461787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7280 + ... + 8361.

It is an arithmetic number, because the mean of its divisors is an integer number (2119491).

Almost surely, 2^8461781 is an apocalyptic number.

It is an amenable number.

8461781 is a deficient number, since it is larger than the sum of its proper divisors (16183).

8461781 is a wasteful number, since it uses less digits than its factorization.

8461781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16182.

The product of its digits is 10752, while the sum is 35.

The square root of 8461781 is about 2908.9140585449. The cubic root of 8461781 is about 203.7764194730.

The spelling of 8461781 in words is "eight million, four hundred sixty-one thousand, seven hundred eighty-one".