651643 has 4 divisors (see below), whose sum is σ = 685960. Its totient is φ = 617328.

The previous prime is 651641. The next prime is 651647. The reversal of 651643 is 346156.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 651643 - 2¹ = 651641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (651641) 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 3 ways as a sum of consecutive naturals, for example, 17130 + ... + 17167.

It is an arithmetic number, because the mean of its divisors is an integer number (171490).

2⁶⁵¹⁶⁴³ is an apocalyptic number.

651643 is a deficient number, since it is larger than the sum of its proper divisors (34317).

651643 is a wasteful number, since it uses less digits than its factorization.

651643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34316.

The product of its digits is 2160, while the sum is 25.

The square root of 651643 is about 807.2440770919. The cubic root of 651643 is about 86.6968353222.

Adding to 651643 its reverse (346156), we get a palindrome (997799).

The spelling of 651643 in words is "six hundred fifty-one thousand, six hundred forty-three".