649871 has 2 divisors, whose sum is σ = 649872. Its totient is φ = 649870.

The previous prime is 649867. The next prime is 649877. The reversal of 649871 is 178946.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 649871 - 2² = 649867 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324935 + 324936.

It is an arithmetic number, because the mean of its divisors is an integer number (324936).

2⁶⁴⁹⁸⁷¹ is an apocalyptic number.

649871 is a deficient number, since it is larger than the sum of its proper divisors (1).

649871 is an equidigital number, since it uses as much as digits as its factorization.

649871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 35.

The square root of 649871 is about 806.1457684563. The cubic root of 649871 is about 86.6181796501.

The spelling of 649871 in words is "six hundred forty-nine thousand, eight hundred seventy-one".