649831 has 16 divisors (see below), whose sum is σ = 825664. Its totient is φ = 497664.

The previous prime is 649829. The next prime is 649843. The reversal of 649831 is 138946.

It is a 11-Lehmer number, since φ(649831) divides (649831-1)¹¹.

It is a cyclic number.

It is not a de Polignac number, because 649831 - 2¹ = 649829 is a prime.

It is a super-4 number, since 4×649831⁴ (a number of 24 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 649793 and 649802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3271 + ... + 3463.

It is an arithmetic number, because the mean of its divisors is an integer number (51604).

2⁶⁴⁹⁸³¹ is an apocalyptic number.

649831 is a deficient number, since it is larger than the sum of its proper divisors (175833).

649831 is a wasteful number, since it uses less digits than its factorization.

649831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250.

The product of its digits is 5184, while the sum is 31.

The square root of 649831 is about 806.1209586656. The cubic root of 649831 is about 86.6164024778.

The spelling of 649831 in words is "six hundred forty-nine thousand, eight hundred thirty-one".