648981 has 6 divisors (see below), whose sum is σ = 937430. Its totient is φ = 432648.

The previous prime is 648971. The next prime is 648997. The reversal of 648981 is 189846.

It is a happy number.

648981 is a `hidden beast` number, since 648 + 9 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 576081 + 72900 = 759^2 + 270^2 .

It is not a de Polignac number, because 648981 - 2⁶ = 648917 is a prime.

It is a super-2 number, since 2×648981² = 842352676722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon 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 648981.

It is not an unprimeable number, because it can be changed into a prime (648911) 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 5 ways as a sum of consecutive naturals, for example, 36046 + ... + 36063.

2⁶⁴⁸⁹⁸¹ is an apocalyptic number.

It is an amenable number.

648981 is a deficient number, since it is larger than the sum of its proper divisors (288449).

648981 is a wasteful number, since it uses less digits than its factorization.

648981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72115 (or 72112 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 648981 is about 805.5935699843. The cubic root of 648981 is about 86.5786203127.

It can be divided in two parts, 64 and 8981, that added together give a triangular number (9045 = T₁₃₄).

The spelling of 648981 in words is "six hundred forty-eight thousand, nine hundred eighty-one".