649581 has 8 divisors (see below), whose sum is σ = 870240. Its totient is φ = 430992.

The previous prime is 649577. The next prime is 649613. The reversal of 649581 is 185946.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 649581 - 2² = 649577 is a prime.

It is a super-2 number, since 2×649581² = 843910951122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 510 + ... + 1248.

It is an arithmetic number, because the mean of its divisors is an integer number (108780).

2⁶⁴⁹⁵⁸¹ is an apocalyptic number.

It is an amenable number.

649581 is a deficient number, since it is larger than the sum of its proper divisors (220659).

649581 is a wasteful number, since it uses less digits than its factorization.

649581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1035.

The product of its digits is 8640, while the sum is 33.

The square root of 649581 is about 805.9658801711. The cubic root of 649581 is about 86.6052934981.

The spelling of 649581 in words is "six hundred forty-nine thousand, five hundred eighty-one".