649191 has 4 divisors (see below), whose sum is σ = 865592. Its totient is φ = 432792.

The previous prime is 649183. The next prime is 649217. The reversal of 649191 is 191946.

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

It is not a de Polignac number, because 649191 - 2³ = 649183 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108196 + ... + 108201.

It is an arithmetic number, because the mean of its divisors is an integer number (216398).

2⁶⁴⁹¹⁹¹ is an apocalyptic number.

649191 is a deficient number, since it is larger than the sum of its proper divisors (216401).

649191 is a wasteful number, since it uses less digits than its factorization.

649191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216400.

The product of its digits is 1944, while the sum is 30.

The square root of 649191 is about 805.7238981190. The cubic root of 649191 is about 86.5879577969.

The spelling of 649191 in words is "six hundred forty-nine thousand, one hundred ninety-one".