651649 has 2 divisors, whose sum is σ = 651650. Its totient is φ = 651648.

The previous prime is 651647. The next prime is 651667. The reversal of 651649 is 946156.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 651249 + 400 = 807^2 + 20^2 .

It is a cyclic number.

It is not a de Polignac number, because 651649 - 2¹ = 651647 is a prime.

Together with 651647, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 651649.

It is not a weakly prime, because it can be changed into another prime (651641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325824 + 325825.

It is an arithmetic number, because the mean of its divisors is an integer number (325825).

2⁶⁵¹⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

651649 is a deficient number, since it is larger than the sum of its proper divisors (1).

651649 is an equidigital number, since it uses as much as digits as its factorization.

651649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 31.

The square root of 651649 is about 807.2477934315. The cubic root of 651649 is about 86.6971014083.

The spelling of 651649 in words is "six hundred fifty-one thousand, six hundred forty-nine".