649381 has 2 divisors, whose sum is σ = 649382. Its totient is φ = 649380.

The previous prime is 649379. The next prime is 649403. The reversal of 649381 is 183946.

649381 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., 624100 + 25281 = 790^2 + 159^2 .

It is a cyclic number.

It is not a de Polignac number, because 649381 - 2¹ = 649379 is a prime.

It is a super-2 number, since 2×649381² = 843391366322, which contains 22 as substring.

Together with 649379, it forms a pair of twin primes.

It is a nialpdrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324690 + 324691.

It is an arithmetic number, because the mean of its divisors is an integer number (324691).

2⁶⁴⁹³⁸¹ is an apocalyptic number.

It is an amenable number.

649381 is a deficient number, since it is larger than the sum of its proper divisors (1).

649381 is an equidigital number, since it uses as much as digits as its factorization.

649381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 31.

The square root of 649381 is about 805.8417958880. The cubic root of 649381 is about 86.5964042620.

The spelling of 649381 in words is "six hundred forty-nine thousand, three hundred eighty-one".