649181 has 4 divisors (see below), whose sum is σ = 699132. Its totient is φ = 599232.

The previous prime is 649157. The next prime is 649183. The reversal of 649181 is 181946.

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

It can be written as a sum of positive squares in 2 ways, for example, as 116281 + 532900 = 341^2 + 730^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649181 is a prime.

It is a super-2 number, since 2×649181² = 842871941522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 649181.

It is not an unprimeable number, because it can be changed into a prime (649183) 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, 24956 + ... + 24981.

It is an arithmetic number, because the mean of its divisors is an integer number (174783).

2⁶⁴⁹¹⁸¹ is an apocalyptic number.

It is an amenable number.

649181 is a deficient number, since it is larger than the sum of its proper divisors (49951).

649181 is a wasteful number, since it uses less digits than its factorization.

649181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49950.

The product of its digits is 1728, while the sum is 29.

The square root of 649181 is about 805.7176924953. The cubic root of 649181 is about 86.5875132005.

The spelling of 649181 in words is "six hundred forty-nine thousand, one hundred eighty-one".