649801 has 2 divisors, whose sum is σ = 649802. Its totient is φ = 649800.

The previous prime is 649799. The next prime is 649813. The reversal of 649801 is 108946.

649801 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 640000 + 9801 = 800^2 + 99^2 .

It is a cyclic number.

It is not a de Polignac number, because 649801 - 2¹ = 649799 is a prime.

Together with 649799, it forms a pair of twin primes.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 649801.

It is not a weakly prime, because it can be changed into another prime (649871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324900 + 324901.

It is an arithmetic number, because the mean of its divisors is an integer number (324901).

2⁶⁴⁹⁸⁰¹ is an apocalyptic number.

649801 is the 361-st centered decagonal number.

It is an amenable number.

649801 is a deficient number, since it is larger than the sum of its proper divisors (1).

649801 is an equidigital number, since it uses as much as digits as its factorization.

649801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 649801 is about 806.1023508215. The cubic root of 649801 is about 86.6150695507.

It can be divided in two parts, 64 and 9801, that multiplied together give a square (627264 = 792²).

The spelling of 649801 in words is "six hundred forty-nine thousand, eight hundred one".