649791 has 24 divisors (see below), whose sum is σ = 1033344. Its totient is φ = 391680.

The previous prime is 649787. The next prime is 649793. The reversal of 649791 is 197946.

649791 is a `hidden beast` number, since 649 + 7 + 9 + 1 = 666.

It is not a de Polignac number, because 649791 - 2² = 649787 is a prime.

649791 is a lucky number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649793) 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 23 ways as a sum of consecutive naturals, for example, 4675 + ... + 4811.

It is an arithmetic number, because the mean of its divisors is an integer number (43056).

2⁶⁴⁹⁷⁹¹ is an apocalyptic number.

649791 is a deficient number, since it is larger than the sum of its proper divisors (383553).

649791 is a wasteful number, since it uses less digits than its factorization.

649791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 188 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 649791 is about 806.0961481114. The cubic root of 649791 is about 86.6146252325.

It can be divided in two parts, 64979 and 1, that added together give a triangular number (64980 = T₃₆₀).

The spelling of 649791 in words is "six hundred forty-nine thousand, seven hundred ninety-one".