649561 has 4 divisors (see below), whose sum is σ = 708624. Its totient is φ = 590500.

The previous prime is 649559. The next prime is 649567. The reversal of 649561 is 165946.

649561 = T₁₀₆ + T₁₀₇ + ... + T₁₇₁.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 649561 - 2¹ = 649559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29515 + ... + 29536.

It is an arithmetic number, because the mean of its divisors is an integer number (177156).

2⁶⁴⁹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

649561 is a deficient number, since it is larger than the sum of its proper divisors (59063).

649561 is a wasteful number, since it uses less digits than its factorization.

649561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59062.

The product of its digits is 6480, while the sum is 31.

The square root of 649561 is about 805.9534726025. The cubic root of 649561 is about 86.6044046566.

It can be divided in two parts, 6495 and 61, that added together give a palindrome (6556).

The spelling of 649561 in words is "six hundred forty-nine thousand, five hundred sixty-one".