646681144 has 16 divisors (see below), whose sum is σ = 1219228920. Its totient is φ = 321553440.

The previous prime is 646681141. The next prime is 646681157. The reversal of 646681144 is 441186646.

It is a junction number, because it is equal to n+sod(n) for n = 646681097 and 646681106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646681141) 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, 221854 + ... + 224749.

Almost surely, 2^646681144 is an apocalyptic number.

It is an amenable number.

646681144 is a deficient number, since it is larger than the sum of its proper divisors (572547776).

646681144 is a wasteful number, since it uses less digits than its factorization.

646681144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 446790 (or 446786 counting only the distinct ones).

The product of its digits is 110592, while the sum is 40.

The square root of 646681144 is about 25429.9261501090. The cubic root of 646681144 is about 864.7622695290.

The spelling of 646681144 in words is "six hundred forty-six million, six hundred eighty-one thousand, one hundred forty-four".