649971 has 32 divisors (see below), whose sum is σ = 1164800. Its totient is φ = 349920.

The previous prime is 649969. The next prime is 649981. The reversal of 649971 is 179946.

649971 is a `hidden beast` number, since 649 + 9 + 7 + 1 = 666.

It is not a de Polignac number, because 649971 - 2¹ = 649969 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

Its product of digits (13608) is a multiple of the sum of its prime factors (216).

It is not an unprimeable number, because it can be changed into a prime (649921) 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 31 ways as a sum of consecutive naturals, for example, 3501 + ... + 3681.

It is an arithmetic number, because the mean of its divisors is an integer number (36400).

2⁶⁴⁹⁹⁷¹ is an apocalyptic number.

649971 is a deficient number, since it is larger than the sum of its proper divisors (514829).

649971 is a wasteful number, since it uses less digits than its factorization.

649971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216 (or 210 counting only the distinct ones).

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

The square root of 649971 is about 806.2077895927. The cubic root of 649971 is about 86.6226222619.

The spelling of 649971 in words is "six hundred forty-nine thousand, nine hundred seventy-one".