648991 has 16 divisors (see below), whose sum is σ = 806400. Its totient is φ = 510048.

The previous prime is 648971. The next prime is 648997. The reversal of 648991 is 199846.

648991 = 18³ + 19³ + ... + 40³.

It is not a de Polignac number, because 648991 - 2⁷ = 648863 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 648991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4600 + ... + 4738.

It is an arithmetic number, because the mean of its divisors is an integer number (50400).

2⁶⁴⁸⁹⁹¹ is an apocalyptic number.

648991 is a deficient number, since it is larger than the sum of its proper divisors (157409).

648991 is a wasteful number, since it uses less digits than its factorization.

648991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198.

The product of its digits is 15552, while the sum is 37.

The square root of 648991 is about 805.5997765640. The cubic root of 648991 is about 86.5790650005.

The spelling of 648991 in words is "six hundred forty-eight thousand, nine hundred ninety-one".